PROCESS OF SYNTHESIS

FIELD

The present disclosure relates to a biosurfactant nano-ferric ionosphere scaffold and, a process of synthesizing the biosurfactant nano-ferric ionosphere scaffold.

DEFINITIONS

As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.

Fenton oxidation process: The term “fenton oxidation process” refers to a process which is used for the treatment of wastewater containing refractory organics. It involves the use of ferrous ion, which act as a catalyst in the decomposition reaction of hydrogen peroxide to hydroxyl ion. The hydroxyl ion/radicals formed in the reaction are responsible for the degradation of refractory organics which results in the formation of hydroperoxyl radicals and conversion of Fe ²⁺ to Fe ³⁺ with the end product as carbon dioxide, water and oxidized compounds.

Hetero-Activated Fenton Catalytic Oxidation (HAFCO) method: The term “HAFCO method” refers to a modified fenton oxidation process, in which the excess ferric ion is prevented from combining with hydroxyl ion by the use of nanoporous activated carbon.

Hydraulic retention time: The term “hydraulic retention time” refers to a measure of the average length of time that any compound remains in a reactor or a process.

BACKGROUND

The background information herein below relates to the present disclosure but is not necessarily prior art.

Landfill leachates are generated from landfills, such as solid waste dumping sites. Leachates pose a major environmental concern due to their high organic and inorganic load, recalcitrants and xenobiotic compounds. During landfilling, the indigenous microorganisms present in the landfill undergo several biotic and abiotic stresses that lead to partial degradation of organic compounds and also cause toxicity to the environment. These recalcitrant molecules are leached out from the landfill in the form of landfill leachate, thereby contaminating the ground water system and other soil environment.

Conventionally, landfill leachates are treated by using various physical, chemical and biological methods. The physical and chemical methods for the treatment of leachates includes coagulation and flocculation, air stripping, chemical precipitation, adsorption and reverse osmosis. However, due to the generation of secondary pollution and high operational costs, these methods are only limited to pre-treatment or post-treatment of leachates, to complement biological treatment processes. The biological treatment processes include high rate anaerobic biological reactors and aerobic biological reactors, sequential biological reactor, moving bed biofilm reactor, membrane bioreactor and conventional activated sludge process. Although many biological methods are available for the leachate treatment, conventional activated sludge process is widely exercised for efficient removal of organic compounds and nutrients. However, high nitrogen requirement, and the presence of recalcitrant compounds characterized by complex structure and high molecular weight negatively alters the efficiency of this process.

Many of the leachate treatment technologies for the removal of toxicants and recalcitrant organics utilize microbes, however they are less efficient in degrading the organics. Complete mineralisation of organics does not take place with microbes in free state or in immobilised state. The enzymatic technology employed for the treatment of landfill leachate also failed because of inactivation of the applied enzymes by the presence of toxicants having very stable delocalised bonds which are resistant to cleavage by enzymes.

Further, homocatalytic and heterocatalytic treatment of landfill leachates also have limited use, as the oxidation potential of toxicants and recalcitrant compounds is very high and the conventional catalytic agents are insufficient to provide sufficient oxidation potential for cleavage of landfill leachates. Moreover, the diffusion of toxicants and refractory compounds to the accessible sites of the homo/heterogenerous catalysts is prevented owing to their geometry, molecular size and high affinity to water molecules in the leachates. In all the above conventional technologies, the microbes or catalysts are exposed to both non- biodegradable and biodegradable organics. Hence, the organics have a tendency to block the active sites making them inactive. The conventional biological systems adopted for landfill leachate treatment, fail to treat the leachate as the recalcitrants pose a destructive effect on the microbial bugs in the biological system. In addition, advanced oxidation processes are also used for the leachate treatment, but these technologies are not effective enough to treat the leachate.

Therefore, there is felt a need for an efficient alternative compound for the treatment of landfill leachates that overcomes the above mentioned limitations.

OBJECTS

Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:

It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.

An object of the present disclosure is to provide a biosurfactant nano-ferric ionosphere scaffold.

Another object of the present disclosure is to provide a process for synthesis of the biosurfactant nano-ferric ionosphere scaffold.

Still another object of the present disclosure is to provide a process for the treatment of landfill leachates using the biosurfactant nano-ferric ionosphere scaffold.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY

The present invention provides a biosurfactant nano-ferric ionosphere scaffold (BS-FIS), which comprises a lipoprotein biosurfactant and a nano-ferric ionosphere scaffold. The lipoprotein biosurfactant is loaded onto the nano-ferric ionosphere scaffold in BS-FIS.

The present disclosure further provides a process for preparing the biosurfactant nano-ferric ionosphere scaffold. The process comprises mixing a predetermined amount of ferrous sulphate and a predetermined amount of ferric chloride in distilled water at a first predetermined temperature for a first predetermined time to obtain a mixture. A basic solution having a flow rate in the range of 1 ml/min to 20 ml/min is added to the mixture until the mixture attains pH 10.0-12.0 to obtain a co-precipitate mixture. The co-precipitate mixture is stirred for a time period in the range of 15 minutes to 60 minutes by using a magnetic stirrer to obtain a slurry. The slurry is settled to obtain a residue comprising ferric ionosphere scaffold. The residue is separated by using external magnetic field to obtain a separated ferric ionosphere scaffold. The separated ferric ionosphere scaffold is washed with water followed by drying at a temperature in the range of 80 °C to 120 °C to obtain the ferric ionosphere scaffold having a particle size in the range of 15 to 20 nm. Separately, lipoprotein biosurfactant is dissolved in a buffer solution having pH 7.0 in an amount in the range of 0.1% w/v to 0.25% w/v to obtain a biosurfactant solution. The ferric ionosphere scaffold is added into the biosurfactant solution to load the lipoprotein biosurfactant from the biosurfactant solution onto the ferric ionosphere scaffold by stirring at a second predetermined temperature for a second predetermined time to obtain a biosurfactant loaded nano-ferric ionosphere scaffold. The biosurfactant loaded nano-ferric ionosphere scaffold is separated to obtain a separated biosurfactant nano-ferric ionosphere scaffold. The separated biosurfactant nano-ferric ionosphere scaffold is washed by using water followed by drying at a temperature in the range of 30 to 50 °C to obtain biosurfactant nano-ferric ionosphere scaffold.

The present disclosure further provides a process for treating the landfill leachate by using biosurfactant nano-ferric ionosphere scaffold. The process comprises collecting leachate comprising toxicant and refractory compound, from a landfill site. The leachate is added in a predetermined amount of lipoprotein biosurfactant at a predetermined pH under stirring for a time period in the range of 15 to 45 min at an ambient temperature to obtain a mixture comprising biosurfactant and leachate. A predetermined amount of ferric chloride solution is added to the mixture comprising biosurfactant and leachate, at a third predetermined temperature for a third predetermined time by mixing uniformly in the presence of rotating magnetic field to obtain a partially coalesced leachate. The partially coalesced leachate is treated with a predetermined amount of biosurfactant nano-ferric ionosphere scaffold at a pH in the range of 6.0 to 8.0, at a temperature in the range of 30 °C to 50 °C followed by aeration for a time in the range of 2 to 6 hours to obtain a coalesced leachate. Further, treating the coalesced leachate for a time in the range of 24 to 48 hours by using hetero-activated fenton catalytic oxidation method to obtain a treated leachate devoid of toxicant and refractory compounds. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The present disclosure will now be described with the help of the accompanying drawing, in which:

Figure 1 illustrates FTIR spectra of (a) nano-ferric ionosphere scaffold (FIS), (b) biosurfactant (BS), and (c) biosurfactant nano-ferric ionosphere scaffold (BS-FIS) in accordance with the present disclosure;

Figure 2 illustrates schematic representation of stages involved in the treatment of landfill leachates using biosurfactant nano-ferric ionosphere scaffold in accordance with the present disclosure;

Figure 3 illustrates GC-MS analysis of (a) raw leachate (leachate comprising toxicants and refractory compounds), and (b) treated leachate devoid of toxicants and refractory compounds in accordance with the present disclosure; and

Figure 4 illustrates a reactor for treating the landfill leachate in accordance with the present disclosure.

LIST OF REFERENCE ALPHABETS

DETAILED DESCRIPTION

Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.

Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.

Numerous hazardous pollutants that emerge from municipal and industrial solid waste are disposed off onto landfills. The incomplete decomposition in the landfills generates huge quantity of toxic compounds and biorecalcitrant compounds in the form of landfill leachate.

The leached components of the landfill leachate percolates into the environment including water bodies such as river, ponds and groundwater system and led to the serious environmental hazards and public health risks. Considerable quantity of recalcitrant compounds was detected in aquatic and terrestrial environment and largely in marine organisms which could successively migrate into the higher tropical levels of food chain and ultimately affects the human life. These recalcitrant compounds are also known to act as a vector for bioaccumulation of many hazardous organic chemicals present in the leachate which ultimately impairs the efficiency of the conventional treatment methods. The main concerns of human and wildlife exposure to these recalcitrant compounds (phenol and lignin derivatives, long chain aliphatic and aromatic compounds) are the potential adverse effects on reproduction, including problems with fertility, the development of new-borns and possess carcinogenicity.

Further, the conventional or prior technologies that addressed the problem of treating the landfill leachate have negative impact on human health due to emission of bioaerosols. Moreover, these technologies remove the dissolved organic compounds only partially and the unconverted compounds remain as persistent organic compounds making the process inefficient.

The present disclosure provides a biosurfactant nano-ferric ionosphere scaffold, and a process of synthesizing the same. The present disclosure further provides a process for treating the landfill leachates using the biosurfactant nano-ferric ionosphere scaffold.

In one aspect, the present disclosure provides a biosurfactant nano-ferric ionosphere scaffold (BS-FIS), which comprises a lipoprotein biosurfactant and a nano-ferric ionosphere scaffold. The lipoprotein biosurfactant is loaded onto the nano-ferric ionosphere scaffold. The biosurfactant nano-ferric ionosphere scaffold is having a structure represented as Formula I,

Formula I

R in Formula I is an alkyl group in cationic heterocyclic amino acid.

The biosurfactant nano-ferric ionosphere scaffold has at least one hydrophilic peptide moiety and at least one hydrophobic long chain alkyl group (Cl 6 to C20) with unsaturated bondings.

The biosurfactant nano-ferric ionosphere scaffold consists of interlinked peptide molecules of biosurfactant through coordinate bonds to form a sphere. The unsaturated covalent bonds in hydrophobic alkyl chain develop cross links with the successive alkyl chains through covalent bond. The cationic heterocyclic amino acid contains tertiary and quaternary nitrogen that interact with ferric ion of nano-ferric ionosphere scaffold through coordinate bonding. The alkyl groups presented in cationic heterocyclic amino acid is bonded with peptide bonds -H-N- C(=O)- through a stable C-C single bond.

In accordance with the present disclosure, the hydrophobic long chain alkyl group (C16-C20) in biosurfactant nano-ferric ionosphere scaffold is polyunsaturated fatty acid (C16-C20). The lipoprotein biosurfactant is polyunsaturated fatty acid (C16-C20) cationic protein biosurfactant is obtained from ethyl fatty esters of edible fats.

In accordance with the present disclosure, an edible fat is used for the preparation of lipoprotein biosurfactant. The edible fat are the animal fats obtained from the source selected from goat, sheep, cow, buffalo, chicken and a mixture thereof.

In another aspect, the present disclosure provides a process for synthesizing the biosurfactant nano-ferric ionosphere scaffold, the process comprising the following steps:

A predetermined amount of ferrous sulphate and a predetermined amount of ferric chloride is mixed in distilled water at a first predetermined temperature for a first predetermined time to obtain a mixture. A basic solution having a flow rate in the range of 1 ml/min to 20 ml/min is added to the mixture until the mixture attains pH 10.0 to 12.0 to obtain a co-precipitate mixture. Stirring the co-precipitate mixture for a time period in the range of 15 minutes to 60 minutes by using a magnetic stirrer to obtain a slurry. The slurry is settled to obtain a residue comprising nano-ferric ionosphere scaffold. Separating the residue by using external magnetic field to obtain a separated nano-ferric ionosphere scaffold. The separated nano- ferric ionosphere scaffold with water is washed followed by drying at a temperature in the range of 80 °C to 120 °C to obtain the ferric ionosphere scaffold having a particle size in the range of 15 to 20 nm. Separately dissolving lipoprotein biosurfactant in a buffer solution having pH 7.0 in an amount in the range of 0.1% w/v to 0.25% w/v to obtain a biosurfactant solution. The nano-ferric ionosphere scaffold is added into the biosurfactant solution to load the lipoprotein biosurfactant from the biosurfactant solution onto the ferric ionosphere scaffold by stirring at a second predetermined temperature for a second predetermined time to obtain a biosurfactant loaded nano-ferric ionosphere scaffold. The biosurfactant loaded nano- ferric ionosphere scaffold is separated to obtain a separated biosurfactant nano-ferric ionosphere scaffold. And the separated biosurfactant nano-ferric ionosphere scaffold is washed using water followed by drying at a temperature in the range of 30 to 50 °C to obtain biosurfactant nano-ferric ionosphere scaffold.

In accordance with the present disclosure, the predetermined amount of ferrous sulphate is in the range of 1 to 2% w/v, and the predetermined amount of ferric chloride is in the range of 2.5 to 4% w/v. In an exemplary embodiment, the predetermined amount of ferrous sulphate is 1.51% w/v, and the predetermined amount of ferric chloride is 3.2% w/v.

In accordance with the present disclosure, the first predetermined temperature is in the range of 75 °C to 95 °C and the first predetermined time period is in the range of 2 to 20 minute. In an exemplary embodiment, the first predetermined temperature is 85 °C and the first predetermined time period is 15 minute.

In accordance with the present disclosure, the second predetermined temperature is in the range of 30 to 45 °C and the second predetermined time period is in the range of 20 to 100 min. In an exemplary embodiment, the second predetermined temperature is 30 °C and the second predetermined time period is 60 min.

In accordance with the present disclosure, the lipoprotein biosurfactant for the synthesis of biosurfactant nano-ferric ionosphere scaffold is polyunsaturated fatty acid (C16-C20) cationic protein biosurfactant obtained from ethyl fatty esters of edible fats.

The amino group of lipoprotein biosurfactant in biosurfactant nano-ferric ionosphere scaffold also conjugate with FciCT (ferric ionosphere backbone) by nucleophilic reaction which results in the N-H bond formation between the lipoprotein biosurfactant and ferric ionosphere backbone. The poly unsaturated fatty acid cationic protein biosurfactant contains two entities: (i) a poly unsaturated fatty acid, as a mean to develop covalent bonds with successive poly unsaturated fatty acid chain; (ii) a head portion, which is formed by cationic peptide (peptides having hyper-conjugated amino acids carry cationic charges due to the presence of quaternary nitrogen). The amino acid in the cationic peptide develops coordinate bond with nano-ferric oxide through carbonyl groups and nitrogen in peptide linkages.

The long chain C16 to C20 polyunsaturated fatty acid in BS-FIS reduces the surface tension between the sequestering compounds (in leachate such as toxicants and recalcitrant compounds) and aqueous media (in leachate). This will help to extend the surface area for long chain hydrocarbon polymers, lignin molecules and cellulose molecules and thereby it increases the availability for sequestration. In accordance with the present disclosure, the amount of the lipoprotein biosurfactant loaded onto the nano-ferric ionosphere scaffold is in the range of 4.0 to 9.0% w/w.

In another aspect, the present disclosure provides a process for treating leachate by using biosurfactant nano-ferric ionosphere scaffold, the process comprises the following steps:

Leachate comprising toxicant and refractory compound is collected from a landfill site. A predetermined amount of lipoprotein biosurfactant in the leachate at a predetermined pH is added under stirring for a time period in the range of 15 to 45 minutes at an ambient temperature to obtain mixture comprising biosurfactant and leachate. A predetermined amount of ferric chloride solution is added to the mixture comprising biosurfactant and leachate, at a third predetermined temperature for a third predetermined time by mixing uniformly in the presence of rotating magnetic field to obtain a partially coalesced leachate. Treating the partially coalesced leachate with a predetermined amount of biosurfactant nano- ferric ionosphere scaffold at a pH in the range of 6.0 to 8.0, at a temperature in the range of 30 °C to 50 °C followed by aeration for a time in the range of 2 to 6 hours to obtain a coalesced leachate. And the coalesced leachate for a time in the range of 24 to 48 hours is treated by using hetero-activated Fenton catalytic oxidation method to obtain a treated leachate devoid of toxicant and refractory compounds.

In accordance with an embodiment of the present disclosure, the leachate is municipal landfill leachate collected from a secured landfill site in Chennai. However, the process of treating the leachates is applicable to all kind of leachate including industrial landfill leachates.

In accordance with the present disclosure, the predetermined amount of lipoprotein- biosurfactant is in the range of 0.1 to 0.25% w/v of the leachate; the predetermined pH is in the range of 6.0 to 8.0. In accordance with an exemplary embodiment, the predetermined pH is 7.0.

In accordance with the present disclosure, the predetermined amount of ferric chloride solution is in the range of 5 to 25% v/v of the biosurfactant treated leachates. The concentration of ferric chloride in the ferric chloride solution is in range of 0.5 to 3.0% (in water). The third predetermined temperature is in the range of 30 to 50 °C, and the third predetermined time is in the range of 30 to 150 minutes. The ferric chloride solution is added drop-wise to the biosurfactant treated leachate. In an exemplary embodiment, the ferric chloride solution is 15% v/v of the biosurfactant treated leachates. The concentration of the ferric chloride solution is 2.0% in water. The third predetermined temperature is 30 °C, and the third predetermined time is 90 minutes.

In accordance with the present disclosure, the predetermined amount of biosurfactant nano- ferric ionosphere scaffold is in the range of 0.02 to 0.10% w/v of partially coalesced leachate. In an exemplary embodiment, the predetermined amount of biosurfactant nano-ferric ionosphere scaffold is 0.08% w/v.

In accordance with the present disclosure, the steps (ii) and (iii) of the process of treating the landfill leachate can be termed as biosurfactant-Fe ³⁺ ion method for the sequestration of high molecular weight recalcitrant components (stage I). The step (iv) of the process of treating the landfill leachate can be termed as biosurfactant nano-ferric ionosphere scaffold method for the sequestration of high molecular weight components and oxidation of low molecular weight components (stage II). The step (v) of the process of treating the landfill leachate can be termed as Hetero Fenton Catalytic Oxidation method for the degradation of residual organics derived from stage I and II.

In accordance with the present disclosure, step (ii), (iii) and (iv) of the process of treating the landfill leachate completely coalesce of the toxicants such as phenol 2, 4 bis (1, 1 -dimethyl ethyl) compounds, heptacosanol, pthalic acid di-(2 -propyl pentyl) ester, eiscosane and n- tetracosanol; and the recalcitrant compounds such as phenol and lignin derivatives, long chain aliphatic and aromatic compounds from the landfill leachate.

In accordance with the present disclosure, the biosurfactant nano-ferric ionosphere scaffold acts as a coalescing agent to form a bonding with recalcitrants of both low and high molecular weight components. The hydrophobic network structure of biosurfactant nano- ferric ionosphere scaffold helps to sequester the long chain hydrocarbon polymers, lignin molecules and cellulose molecules. The hydrophilic peptide network structure of biosurfactant nano-ferric ionosphere scaffold helps to sequester the low molecular weight organic compounds. The low molecular weight organic compounds are oxidized by hydroxyradical generated from molecular oxygen abstracted air through redox reaction as shown below. H0 ₂ + H ⁺ 2OH'

RH + HO ^ R' + H ₂ Q

RH + HO' -> ROH’ (contributes to biodegradability)

R' + HO' C 2 + H ₂ (contributes to COD reduction) The schematic representation of sequestration and oxidation of refractory organics using biosurfactant nano-ferric ionosphere scaffold is illustrated in Formula II:

Formula II

The amino group (NH2) of the lipoprotein biosurfactant in biosurfactant nano-ferric ionosphere scaffold conjugates with OH group of toxicants and refractory organics through N-H bonding by nucleophilic reaction (elimination of H2O), and thus it mediates the removal of these toxicants and refractory compounds from the leachate.

The hydroxyl radicals in biosurfactant nano-ferric ionosphere scaffold combine with low molecular weight refractory organic compounds to convert into soluble biodegradable organic compounds. The sequestered high molecular weight organic compounds form settleable solids along with biosurfactant nano-ferric ionosphere scaffold. The biosurfactant nano-ferric ionosphere scaffold has unique properties such as smaller size, high surface area, and their magnetic property and thus can be easily removed from the aqueous media using an external magnetic field for reuse. Thus, the biosurfactant nano-ferric ionosphere scaffold is a recyclable mass for few cycles without addition of fresh charges.

In accordance with the present disclosure, the lipoprotein biosurfactant nano-ferric ionosphere scaffold is recyclable for at least 10 cycles.

Further, the residual biodegradable and non-toxicant compounds present in the leachate obtained after step (iv) are degraded using the hetero-activated fenton catalytic oxidation method, without the production of any secondary emission.

In accordance with the present disclosure, the hetero-activated Fenton catalytic oxidation method comprises treating the coalesced leachate using nanoporous activated carbon in an amount in the range of 2.0 to 4.0% w/v of the coalesced leachate, ferric nano-metal oxide in an amount in the range of 0.3 to 0.9% w/v of the coalesced leachate, hydrogen peroxide in an amount in the range of 10 to 30% v/v of the coalesced leachate, and potassium permanganate in an amount in the range of 0.002 to 0.006% w/v of the coalesced leachate in the presence of air.

In an exemplary embodiment, the hetero-activated Fenton catalytic oxidation method comprises treating the coalesced leachate using nanoporous activated carbon in an amount of 3.0% w/v of the coalesced leachate, ferric nano-metal oxide in an amount of 0.6% w/v of the coalesced leachate, and hydrogen peroxide in an amount of 0.02% v/v of the coalesced leachate, and potassium permanganate in an amount 0.004% w/v of the coalesced leachate in the presence of air.

In accordance with the present disclosure, hetero-activated fenton catalytic oxidation method is a modification of fenton process, in which the excess ferric ion is prevented from combining with hydroxyl ion by the use of nanoporous activated carbon.

The fenton oxidation process is an advanced oxidation process, which is used for the treatment of wastewater containing refractory organics. It involves the use of ferrous ion, which act as a catalyst in the decomposition reaction of hydrogen peroxide to hydroxyl ion. The hydroxyl radicals formed in the reaction are responsible for the degradation of refractory organics which results in the formation of hydroperoxyl radicals and conversion of Fe ²⁺ to Fe ³⁺ with the end product as carbon dioxide, water and oxidized compounds.

H ₂ O ₂ + Fe ²⁺ Fe ^{3 +} + OH~ + OH (1) OH + RH H _Z O + R (2)

The main disadvantage of the conventional fenton process is the precipitation of ferric ion with hydroxide ion to form ferric hydroxide sludge as suggested by above eq. 1. The ferrous ion is extensively used in the process which also leads to heavy metal pollution. Thus, the ferric hydroxide sludge formation and heavy metal pollution are the major drawbacks of the conventional fenton process. Therefore, to overcome the drawbacks of fenton process, the hetero-activated fenton catalytic process involve addition of nanoporous activated carbon to the fenton reagents which prevents the ferric hydroxide sludge formation by acting as a second phase matrix and also it acts as heterogeneous catalyst to reduce the activation energy required for the oxidation of refractory organics present in leachate.

In accordance with the present disclosure, the reactants used in the hetero-activated fenton process are nanoporous activated carbon, ferric nano-metal oxide, hydrogen peroxide and potassium permanganate.

The present technology involves sequestration of complicated toxicants and recalcitrant compounds presented in the landfill leachate. The residual biodegradable organics are treated through hetero-activated catalytic oxidation method. It can reduce the high chemical oxygen demand (COD) from leachate through simultaneous sequestration and homogeneous catalytic oxidation and to increase biodegradable index of the leachate.

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure. The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.

Experimental details:

Experiment 1: Experimental setup for the synthesis of nano- ferric ionosphere scaffold

The nano-ferric ionosphere scaffold was synthesized by co-precipitation method as follows:

The iron compounds such as ferrous sulphate (1.51 g) and ferric chloride (3.2 g) were mixed in 100 ml of distilled water at 85 °C for 15 minutes to obtain a mixture. IN NaOH was added at a flow rate of 3 ml/min until the solution mixture attains pH 12.0 to obtain a coprecipitated mixture. Then co-precipitated mixture was stirred for 30 minutes using magnetic stirrer to obtain a slurry. The slurry was settled to obtain a residue comprising nano- ferric ionosphere scaffold. The residue comprising nano-ferric ionosphere scaffold was separated using external magnetic field to obtain separated nano-ferric ionosphere scaffold. Washing the separated nano-ferric ionosphere scaffold with deionized water thrice and then dried at 110°C in hot air oven to obtain a nano-ferric ionosphere scaffold having the particle size in the range of 15 nm to 20 nm.

Experiment 2: Experimental setup for the synthesis of biosurfactant nano-ferric ionosphere scaffold from nano-ferric ionosphere scaffold.

The optimization of the process of synthesis of biosurfactant nano-ferric ionosphere scaffold was carried out by varying the reaction time (20, 40, 60, 80, 100 min), pH (6.0, 6.5, 7.0, 7.5, 8.0), temperature (30, 35, 40, 45°C), the mass of nano-ferric ionosphere scaffold (0.5, 0.75, 1, 1.25, 1.5 g) and the initial concentrations of lipoprotein biosurfanctant (2.5, 5, 7.5, 10 mg/1). The process of synthesizing the biosurfactant nano-ferric ionosphere scaffold from nano- ferric ionosphere scaffold is as follows:

Separately, 15 mg of polyunsaturated fatty acid cationic protein biosurfactant was dissolved in 10 ml pH 7.0 phosphate buffer (0.1 M) to obtain a biosurfactant solution. The nano-ferric ionosphere scaffold was added into the biosurfactant solution to load the lipoprotein biosurfactant onto the nano-ferric ionosphere scaffold by stirring at a temperature of 30°C for 60 min at pH 7.0 to obtain the biosurfactant loaded nano-ferric ionosphere scaffold. The biosurfactant loaded nano-ferric ionosphere scaffold were then separated from the buffer solution to obtain the separated biosurfactant nano-ferric ionosphere scaffold. Washing the separated biosurfactant nano-ferric ionosphere scaffold with distilled water and dried at 40°C which removes the moisture to obtain biosurfactant nano-ferric ionosphere scaffold.

The maximum loading capacity of lipoprotein biosurfactant onto the nano-ferricionosphere scaffold was estimated based on the residual protein concentration using one variable at a time approach.

The optimum conditions for the maximum loading of lipoprotein biosurfactant onto carrier matrix (nano-ferric ionosphere scaffold) was found to be time (60 minutes), pH (7.0), temperature (30°C), the mass of ferric ionosphere scaffold (1 g) and the initial concentrations of lipoprotein biosurfactant (7.5 mg).

At the optimized conditions, loading percentage of biosurfactant was achieved to be 90.12 ± 1.2% (i.e. 6.75 mg/g of ferric ionosphere scaffold).

The lipoprotein biosurfactant of the present disclosure is polyunsaturated fatty acid (Cl 6- C20) cationic protein biosurfactant (lipoprotein biosurfactant) obtained from ethyl fatty esters of edible fats.

Experiment 3: Fourier transform infrared (FTIR) analysis of biosurfactant, nano-ferric ionosphere scaffold and biosurfactant nano-ferric ionosphere scaffold

The FTIR spectrum of nano-ferric ionosphere scaffold (Figure 1 (a)) showed that the peak at 575 cm ^-1 corresponding to the absorption band of Fe-0 due to the stretching vibration of the ferric-oxygen absorption peak (Fe-0 bonds in the crystalline lattice of FciOj. The FTIR spectrum of BS is shown in the Figure 1 (b). The FTIR spectrum of biosurfactant shows the peaks at 3130, 2923, 1647, 1104 cm ^-1 corresponding to O-H stretching, C-H stretching, amide groups, and C-0 stretching vibration of carboxylic acids, respectively (Figure 1 (b)).

The peaks at 2923 cm ^-1 in BS and 2928 cm ^-1 in biosurfactant nano-ferric ionosphere scaffold as shown in Figure 1 (c) may be attributed to asymmetrical C-H bending vibrations and peaks at 2860 cm ^-1 in BS, and 2857 cm ^-1 in biosurfactant nano-ferric ionosphere scaffold may be due to the symmetrical stretching vibration of CH groups present in the biosurfactant. The peaks attributed to N-H bending vibrations in the FT-IR spectrum of biosurfactant at 1647 cm ^-1 was shifted to 1630 cm ^-1 in biosurfactant nano-ferric ionosphere scaffold. The peak corresponding to C-0 stretching vibration of carboxylic acid at 1104 cm ^-1 in FTIR spectrum of BS also shifted to 1119 cm ^-1 in biosurfactant nano-ferric ionosphere scaffold. The peaks at 575 cm ^-1 attributing to Fe-0 bond was observed in biosurfactant nano-ferric ionosphere scaffold and was absent in FTIR spectrum of BS suggesting that the immobilized biosurfactant (biosurfactant nano-ferric ionosphere scaffold) has the characteristic peaks of both the ferric ionosphere scaffold and the BS. These FTIR results confirmed the immobilization of biosurfactant to the ferric ionosphere scaffold.

Experiment 4: Process of treating the landfill leachate using three stages. The process is represented schematically using Figure 2.

Stage I: Experimental setup for Stage I treatment of landfill leachate using surface active biomolecule- ferric ion method

The removal of toxicants and refractory organics from the landfill leachate using surface active biomolecules (lipoprotein Biosurfactant) -Ferric (Fe) ion method was carried out by optimizing the conditions such as time (30, 60, 90, 120, 150 min.), pH (6.0, 6.5, 7.0, 7.5, 8.0), temperature (30, 35, 40, 45, 50°C), initial concentrations of lipoprotein biosurfactant (1, 1.5, 2.0, 2.5 mg/1) and volume of 2% ferric chloride solution (5, 10, 15, 20 and 25 ml). Further, the optimized conditions of the process of treating landfill leachate using surface active biomolecule- ferric ion method (stage I) is as follows:

The municipal landfill leachate comprising toxicant and refractory compound was collected from a secured landfill site in Chennai to obtain leachate. Initially, 1.5 mg of lipoprotein biosurfactant was mixed to the 100 ml of the leachate, and it was stirred at 400 rpm for 30 min under room temperature to obtain a mixture comprising biosurfactant and leachate. Further, adding 15 ml of 2.0% ferric chloride solution (2 g of ferric chloride dissolved in 100 ml of distilled water) drop wise at a flow rate of 2 ml/min to a mixture comprising biosurfactant and leachate. Then, this mixture was uniformly stirred in magnetic stirrer at 400 rpm at a temperature of 30°C and pH 7.0 for a time period of 90 minutes to obtain the partially coalesced leachate. The reduction in chemical oxygen demand (COD), ammoniacal nitrogen and lignin content of the partially coalesced leachate was measured to check the efficiency of process. At the optimized conditions, a significant decrease in the chemical oxygen demand (COD) from the initial 18,930 ppm to 2,540 ppm, ammoniacal nitrogen from 1,624 ppm to 624 ppm, and lignin from 12,052 ppm to 682 ppm was achieved in 2 hours of treatment process by using lipoprotein biosurfactant -Fe ³⁺ ion method.

STAGE II: Experimental setup for Stage II treatment of landfill leachate using biosurfactant nano-ferric ionosphere scaffold treatment

The partially coalesced leachate obtained using the biosurfactant Fe-ion method was further treated with biosurfactant nano-ferric ionosphere of the present disclosure. The process conditions of treating the partially coalesced leachate using biosurfactant nano-ferric ionosphere scaffold treatment was optimized for the efficient treatment of leachate by varying the time (1, 2, 3 and 4 hours), pH (6.0, 6.5, 7.0, 7.5 and 8.0), temperature (30, 35, 40, 45 and 50°C), and initial mass of lipoprotein biosurfactant ferric ionosphere scaffold (20, 40, 60, 80 and 100 mg). The optimal process conditions for treating the partially coalesced leachate using biosurfactant nano-ionosphere scaffold is as follows:

The biosurfactant nano-ferric ionosphere scaffold (80 mg) was mixed with the partially coalesced leachate (100 ml) at pH 7.0 and temperature 30 °C followed by aeration to initiate the treatment process for 4 hours to obtain the coalesced leachate. The reduction in COD, ammoniacal nitrogen and lignin was measured to check the treatment process efficiency. At the optimized conditions, a significant decrease in the COD from 2,540 ppm to 1,724 ppm, ammoniacal nitrogen from 624 ppm to 324 ppm, and complete removal of lignin was achieved in 4 hours of treatment process by using biosurfactant nano-ferric ionosphere scaffold. The biosurfactant nano-ferric ionosphere scaffold were then recovered from the coalesced leachate and it showed the efficient reusability upto 10 cycles.

STAGE III: Experimental setup for Stage III treatment of landfill leachate using heteroactivated catalytic oxidation method

The coalesced leachate was then treated using heter-activated catalytic oxidation method. The process optimized conditions are as follows:

To 100 ml of coalesced leachate, nanoporous activated carbon (3 g), ferric nano-metal oxide (0.6 g), hydrogen peroxide (20 pl) and potassium permanganate (4 mg) was mixed uniformly and aerated to initiate the treatment process to obtain leachate devoid of toxicants and refractory compounds. The reduction in COD, ammoniacal nitrogen and lignin was measured to check the treatment process efficiency. At the optimized conditions, a significant decrease in the COD from 1,724 ppm to 220 ppm, ammoniacal nitrogen from 324 ppm to 112 ppm was achieved in 36 hours of treatment process.

Experiment 5: Characterization of three stage treated leachate (leachate devoid of toxicants and refractory compounds) using GC-MS

The treatment studies were carried out by subjecting the raw leachate (leachate comprising toxicants and refractory compounds) for the three stage treatment processes and the treated samples were characterized and the removal of toxicants and refractory organics were confirmed using GC-MS analysis. The GC-MS spectra of raw leachate (leachate comprising toxicants and refractory compounds) and treated leachate devoid of toxicants and refractory compounds are presented in Figure 3. The sample preparation for GC-MS analysis is performed as follows: 50 ml of raw leachate was extracted using 1:1 ratio of leachate and dichloromethane mixture and then 1 ml of the sample was subjected to GC-MS analysis. The chromatogram of raw leachate shows that it contains numerous toxicants and refractory organics of range between C11-C30 (Figure 3 (a)). Further, the treated leachate (50 ml) was subjected to extraction with 50 ml of dichloromethane and was examined using GC-MS analysis.

In the Figure 3 (b), the GC-MS chromatogram shows that the majority of toxicants and refractory organics presented in the raw leachate were removed by the three stage treatment process. This confirms the efficiency of present treatment process for the removal of toxicants and refractory organics from the landfill leachate.

Experiment 6: Reactor for treating the landfill leachates

Figure 4 illustrates a wastewater inlet (A) is fixed at the top of the reactor to distribute the Municipal leachate. An external electromagnetic field (B) is fabricated at the hopper bottom to separate the biosurfactant nano-ferric ionosphere from the treated municipal leachate at an inclination of 0 (45-50°). An external electromagnetic screw conveyor is provided at the treated water outlet to removed the settled biosurfactant nano-ferric ionosphere from the treated municipal leachate. The treated water outlet provided at the bottom (C) is used to remove the treated municipal leachate under batch mode operation. An air injection devices (D) injects air to serve two purposes. The first one is for the fluidization of biosurfactant nano-ferric ionosphere for the effective binding with the low molecular weight lignin molecules and bio refractory organic compounds in the leachate. The second purpose is that the molecular oxygen of injected air is used for the generation of hydroxyl radical for the oxidation of scavenged organic molecules by biosurfactant nano-ferric ionosphere. The treated water outlet (E) provided at the top of the reactor is to remove the treated municipal leachate under continuous mode of operation.

Experiment 7: Process for producing lipoprotein biosurfactant

Animal fat oil was prepared by heating the animal fat at 100°C-150°C for 1 h, and then filtered to obtain a molten fat. A solution of concentrated sulfuric acid H2SO4 (2.0% based on the oil weight) in ethanol (50-70% v/v) was heated to 50-80°C and was added to the molten fat. The mixture was well stirred, placed into the water bath and shaker for heating and then agitated simultaneously at 50-80°C for 1 h. The esterified animal fat was removed from the water bath shaker and decanted into a separating funnel and allowed to separate for 12 hours. The esterified oil was at the bottom of the separating funnel. The esterified oil was used in the biosurfactant preparation.

In accordance with the present disclosure, the biosurfactant nano-ferric ionosphere scaffold can be separated with the help of external magnetic field for the reuse applications. Thus, the biosurfactant nano-ferric ionosphere scaffold is a recyclable mass for few cycles without addition of fresh charges. The BS-ferric ionosphere is recyclable for at least 10 cycles. The present biosurfactant nano-ferric ionosphere scaffold significantly reduces COD of the leachate through simultaneous sequestration and homogeneous catalytic oxidation and increases biodegradable index of the leachate.

The presence of toxicants and refractory organics in the leachate have contributed to lower treatment efficiencies even with higher hydraulic retention time (HRT) and thus the foot print area requirement. Leachate toxicity and the refractory organics are the major issues which require assessment and consideration in the design and optimization of landfill leachate treatment process. The three stage leachate treatment process involving the use of recyclable biosurfactant nano-ferric ionosphere scaffold provides a better treatment process with a HRT of 42 hours, which is significantly lower compared to other conventional leachate treatment technology. The present three stage treatment process also provides a significant advantage of low foot print area over the existing technologies.

The present invention provides the use of lipoprotein biosurfactant in the scaffold to sequester the high molecular weight and low molecular weight organic compounds in the present leachate treatment technology. It involves the use of biosurfactant nano-ferric ionosphere scaffold (STAGE II) for the efficient and complete coalescence of toxicant and refractory organics from the landfill leachate. It works on the removal of toxicants and refractory organics only by coalescence into a stable and non-leachable solid product which can be disposed off as a fuel and thereby preventing the emission of any secondary emission. In addition, the biosurfactant nano-ferric ionosphere scaffold provides the simultaneous sequestration of high molecular weight soluble/miscible natural and synthetic organic compounds present in the leachate and also the oxidation of soluble low molecular weight refractory organic compounds into biodegradable water soluble organic compounds. Hence, the generation of any secondary emission is prevented in the present process.

In accordance with the present disclosure, the biosurfactant nano-ferric ionosphere scaffold is employed, but not limited to treat the leachates from other secured landfill, hazardous solid waste dump site and non-hazardous solid waste dumped site. It can be applied to any other type of landfill leachate^

Thus, the society will be relieved of the problems faced by the disposal of municipal solid waste using the present process of treatment of landfill leachates.

TECHNICAL ADVANCEMENTS

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of: a biosurfactant ferric ionosphere scaffold which oxidize soluble low molecular weight refractory organic compounds into biodegradable water soluble organic compounds; is recyclable for at least 10 cycles of landfill leachate treatment; completely removes toxicants and refractory organics from the landfill leachates; and simultaneously sequestrate high molecular weight soluble/miscible natural and synthetic organic compounds present in the leachate; and a process for synthesizing biosurfactant ferric ionosphere scaffold which involves simple steps that can be scaled up easily; is economical; and environment friendly and a process for treating landfill leachates, which can be applied to land fill/ secured land fill sites to remove/treat the constituents of leachate into a disposable non-hazardous solid product; can also be applied to pharmaceutical industry, chemical industry, paper and pulp industry, tanning industry, etc for the removal of biorefractory organics from reverse osmosis reject stream; less footprint area requirement for the treatment process to be established; low retention time; treatment time required is less as compared to conventional technologies; no secondary emissions in the form of liquid, solid and gaseous components; no odour emission; can be applied for the complete treatment of landfill leachate; prevent the contamination of ground water and rivers with organic compounds, metals and recalcitrant compounds; prevent chronic toxin accumulation of toxic organic compounds and organic compounds in life cycle; prevent eutrophication of aquatic systems; requires very short hydraulic retention time; and prevent accumulative and detrimental effect on the ecology and food chains leading to carcinogenic effects, acute toxicity and genotoxicity among human beings.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.

Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.

While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.