DESC:FIELD
The present disclosure relates to an adsorbent composition and a process for preparing the same. The present disclosure particularly relates to an adsorbent composition for simultaneously reducing the content of anionic and cationic pollutants from the waste water.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Waste water treatment protects and maintains the sources of water for domestic, industrial, environmental and agricultural use; and prevents the spread of diseases. Treatment of the waste water removes organic and inorganic pollutants from the waste water, so that it can be disposed of without adversely affecting the environment. Generally, the waste water is subjected to pre-treatment steps, such as filtration, chlorination and sedimentation, prior to the actual treatment. Various physical, chemical, and biological methods are known for treating the waste water, such as, adsorption, membrane separation, chemical precipitation, ion exchange, and use of microorganisms, such as bacteria. Usually, a combination of physical, chemical and biological methods are used for the treatment of the waste water. However, these known methods have certain drawbacks, such as use of expensive material, need of skilled technicians, time consuming, and inefficient removal of the pollutants. Adsorption processes are typically used to remove dissolved pollutants that remain after various treatment processes.
However, the conventional adsorbents are expensive, difficult to regenerate and dispose of. Further, the known adsorbents for the waste water treatment are capable of removing either anionic or cationic pollutants, which limits their application.
Therefore, there is a felt a need for an alternative adsorbent that mitigates the drawbacks mentioned herein above.
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.
Another object of the present disclosure is to provide an adsorbent composition for simultaneously reducing the content of anionic and cationic pollutants from the waste water.
Still another object of the present disclosure is to provide a process for preparation of the adsorbent composition.
Yet another object of the present disclosure is to provide a process for simultaneously reducing the content of anionic and cationic pollutants from the waste water.
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 disclosure relates to an adsorbent composition for simultaneously reducing the content of anionic and cationic pollutants from the waste water. The adsorbent composition comprises at least one surface modified mineral selected from bentonite and attapulgite in an amount in the range of 10 to 40 wt% of the total weight of the adsorbent composition; activated bauxite in an amount in the range of 50 to 80 wt% of the total weight of the adsorbent composition and at least one filler selected from siliceous earth and kaolin in an amount in the range of 5 to 30 wt% of the total weight of the adsorbent composition.
The present disclosure further relates to a process for preparing the adsorbent composition. The process comprises treating at least one mineral selected from bentonite and attapulgite with a mineral acid for a time period in the range of 1 hour to 20 hours to obtain a surface modified mineral. Bauxite is separately activated at a temperature in the range of 400 to 700 ºC for a time period in the range of 1 hour to 5 hours to obtain an activated bauxite. In the next step, the surface modified mineral is mixed with the activated bauxite to obtain a first mixture followed by addition of at least one filler selected from siliceous earth and kaolin to the first mixture to obtain a second mixture. Water is added to the second mixture to obtain a dough. The dough is extruded through an extruder followed by drying at a temperature in the range of 300 to 700 ºC to obtain a dried mixture. Finally the dried mixture is sized to obtain the adsorbent composition.
The present disclosure also relates to a process for simultaneously reducing the content of anionic and cationic pollutants from the waste water by contacting the the waste water with the adsorbent composition of the present disclosure at a temperature in the range of 25 °C to 35 °C to obtain a treated water, wherein the reduction in the content of anionic and cationic pollutants is greater than 90%.
DETAILED DESCRIPTION
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.
The quality of water world-wide is deteriorating rapidly due to human activities, increase in population, and industrialization. Recent awareness has led to the development of various methods for removing pollutants from the water. Adsorbents are commonly used for the treatment of the waste water. However, known adsorbents for the treatment of the waste water require high capital cost. Further, the capacity of conventional adsorbent deteriorates with each regeneration cycle. Moreover, the adsorbent regeneration generally requires steam or vacuum treatment, and spent adsorbent has to be disposed of. Further, known adsorbents for the waste water treatment are capable of removing either anionic or cationic pollutants, which limits their application.
The present disclosure therefore, provides an adsorbent composition for simultaneously reducing the content of anionic and cationic pollutants from the waste water.
In a first aspect, the present disclosure provides an adsorbent composition for simultaneously reducing the content of anionic and cationic pollutants from the waste water. The adsorbent composition comprises at least one surface modified mineral selected from bentonite and attapulgite in an amount in the range of 10 to 40 wt% of the total weight of the adsorbent composition; activated bauxite in an amount in the range of 50 to 80 wt% of the total weight of the adsorbent composition and at least one filler selected from siliceous earth and kaolin in an amount in the range of 5 to 30 wt% of the total weight of the adsorbent composition.
Typically, the waste water comprises anionic pollutants such as sodium fluoride, calcium fluoride, potassium fluoride, magnesium fluoride and cationic pollutants such as zinc oxide, zinc acetate, zinc chloride, lead oxide, lead acetate, lead chloride.
The adsorbent composition of the present disclosure comprises different phases of metal-oxides, which aids in the generation of active sites and enhances the adsorption capacity of the adsorbent composition of the present disclosure. The AlOOH (boehmite) phase present in bauxite has a tendency to bond due to affinity towards anions and cations, such as fluoride, arsenic, cadmium, zinc and lead, which enhances the adsorption process.
Typically, the adsorbent composition of the present disclosure is characterized by having a surface area in the range of 90 m2/g to 110 m2/g; an adsorption capacity for anions in the range of 2.0 mg/g to 2.4 mg/g; an adsorption capacity for cations in the range of 3.8 mg/g to 4.6 mg/g and loss on ignition in the range of 5 wt% to 12 wt% of total weight of the adsorbent composition.
In a second aspect, the present disclosure provides a process for preparing the adsorbent composition. The process comprises treating at least one mineral selected from bentonite and attapulgite with a mineral acid for a time period in the range of 1 to 20 hours to obtain a surface modified mineral.
In an embodiment, the mineral acid is selected from sulfuric acid and hydrochloric acid.
In an exemplary embodiment, the mineral acid is 30 % to 70 % aqueous sulfuric acid solution.
The acid treatment is carried out using known techniques, such as spraying, wet mixing, dipping, and the like. The time period for acid activation depends on the requirement. In an embodiment, when the acid activation is carried out for about 20 hours, positive charge is created on the surface of the calcined material and also the surface area value is increased, which leads to an increase in the adsorption capacity of the adsorbent composition of the present disclosure.
The surface modified mineral is washed using at least one fluid medium selected from water, acidic solution and basic solution. Typically, the time period for washing is in the range of 10 minutes to 40 minutes depending upon the adsorbent quantity.
Bauxite is separately activated at a temperature in the range of 400 to 700 ºC for a time period in the range of 1 to 5 hours to obtain an activated bauxite.
The surface modified mineral is then mixed with the activated bauxite to obtain a first mixture.
Typically, the ratio of the surface modified mineral to the activated bauxite is in the range of 1:1.5 to 1:9. In an exemplary embodiment of the present disclosure, the ratio is 1:2.5.
In the next step, at least one filler is added to the first mixture to obtain a second mixture. The filler is selected from siliceous earth and kaolin.
Water is added to the second mixture to obtain a dough.
The dough is extruded through an extruder; followed by drying at a temperature in the range of 300 to 700 ºC to obtain dried extrudates. Finally the dried extrudates are sized to obtain the adsorbent composition.
Typically, sizing is done by known methods, such as crushing and sieving, to separate out the required fraction.
In a third aspect, the present disclosure provides a process for simultaneously reducing the quantity of anionic and cationic pollutants from the waste water by contacting the waste water with the adsorbent composition of the present disclosure at a temperature in the range of 25 °C to 35 °C to obtain a treated water, wherein the reduction in the content of anionic and cationic pollutants is greater than 90%.
In one embodiment of the present disclosure, the process for simultaneously reducing the quantity of anionic and cationic pollutants from the waste water is done by agitation method.
In another embodiment, the process for simultaneously reducing the quantity of anionic and cationic pollutants from the waste water is carried out by passing the waste water through a bed of adsorbent composition for a time period ranging from 5 to 15 minutes and at a flow rate of the waste water in the range of 5 L/h to 50 L/h.
Typically, the working pH for removal of anions is in the range of 5 to 7 and for removal of cations, the working pH is in the range of 7.5 to 8.0.
The adsorbent composition of the present disclosure is capable of simultaneously removing anionic pollutants such as fluoride and arsenic and cationic pollutants such as lead, zinc and copper. The active sites generated due to the different phases of the metal-oxides, enhance the adsorption capacity of the adsorbent composition of the present disclosure. The adsorbent composition is capable of effectively reducing the anionic and cationic pollutants, wherein the anionic and cationic pollutants in the treated water is within the permissible limit for portable quality water which becomes re-usable or dis-chargeable as per the quality standards.
The adsorbent composition of the present disclosure can be regenerated and reused multiple times without affecting its adsorption capacity. The adsorbent composition is regenerated using at least one acid and alkali. The alkali used for regenerating the adsorbent composition is at least one selected from sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide. The acid used for regenerating the adsorbent composition is at least one selected from hydrochloric acid, sulphuric acid, nitric acid, perchloric acid and phosphoric acid.
In an embodiment, the adsorbent composition of the present disclosure is regenerated up to 3 times with an efficiency of removing the anionic and cationic pollutants of more than 90 %.
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: Preparation of the adsorbent composition in accordance with the present disclosure
Example-1:
Minerals like bentonite and attapulgite were mixed in the ratio of 9:1 and mixed in 30% H2SO4 solution in a hot shaker bath of 80 ºC for overnight to obtain an admixture. The admixture was washed with water till the pH of the solution became 4 to obtain a surface modified mineral.
1500 g of bauxite was separately calcined at 500 ºC for 1 h to obtain an activated bauxite.
The surface modified mineral (600 g) was mixed with the activated bauxite (1500 g) in the ratio of 1:2.5 to obtain a homogeneous mixture. 525 ml of water was added to the homogeneous mixture to obtain a dough.
The dough was extruded through an extruder; followed by drying at 400 ºC to obtain a dried extrudates. The dried extrudates were crushed and sieved to obtain the desired size and shape of the adsorbent composition.
Example-2:
Same experimental procedure was followed as described in example-1, except that only bentonite (1000 g) was used.
Example-3:
Same experimental procedure was followed as described in example-1, except that only attapulgite (1000 g) was used.
Comparative example-4:
Bentonite and attapulgite were mixed in the ratio of 9:1 and mixed in 30% H2SO4 solution in a hot shaker bath of 80 ºC for overnight to obtain an admixture. Then the admixture was washed with water till the pH of the solution became 4 to obtain a surface modified mineral.
The so obtained surface modified mineral was used as the adsorbent.
Comparative example-5:
Bauxite was calcined at 500 ºC for 1 h to obtain an activated bauxite.
The so obtained activated bauxite was used as the adsorbent.
Experiment 2: Treatment of waste water for simultaneously reducing the content of anionic and cationic pollutants by using adsorbent composition prepared in examples 1-5 by Agitation method
Trial 1: Waste water (100 ml) having anionic content (fluoride compounds 17.2 ppm) and cationic content ( zinc compounds 4.5 ppm and lead compounds 45.6 ppm) was stirred for 60 minutes with 50 mg of adsorption composition of example 1. After the treatment, the treated water was analysed for fluoride, zinc and lead contents in treated water.
Trial 2: Same experimental procedure was followed as described in Trial 1, except that the adsorbent composition of Example-2 was used.
Trial 3: Same experimental procedure was followed as described in Trial 1, except that the adsorbent composition of Example-3 was used.
Trial 4: Same experimental procedure was followed as described in Trial 1, except that the adsorbent of Example-4 was used.
Trial 5: Same experimental procedure was followed as described in Trial 1, except that the adsorbent of Example-5 was used.
Typically, the adsorbent composition of the present disclosure has an efficiency of more than 90 % for the removal of the anionic and cationic pollutants from the waste water, as summarized in Table-1.
Table-1: Reduction of anionic and cationic contents from the waste water using the adsorbent composition of the present disclosure.
Adsorbent composition of Examples 1-5 Feed Fluoride compounds (ppm)
(Anionic pollutants) Zinc compounds (ppm)
(Cationic pollutants) Lead compounds (ppm)
(Cationic pollutants)
Waste water 17.2 4.5 45.6
Example-1 Treated water 1.8 0.2 0.4
Example-2 Treated water 7.4 1.2 6.2
Example-3 Treated water 4.8 2.6 12.4
Example-4 Treated water 6.27 2.3 4.2
Example-5 Treated water 8.91 1.4 0.8
It is seen from Table-1 that the adsorbent composition of the present disclosure is capable of removing pollutants, such as fluoride and lead with more than 90% efficiency. Further, it is evident that the adsorbent composition comprising the surface modified mineral along with activated bauxite is capable of simultaneously removing cationic and anionic pollutants. Furthermore, it is observed that the adsorbent composition comprising the combination of minerals has greater adsorbtion efficiency as compared to the adsorbent composition comprising a single mineral.
Experiment 3: Regeneration of the adsorbent composition
5 g of saturated adsorbent composition was stirred in 1% NaOH solution for 15 minutes followed by filtering to obtain a partially regenerated adsorbent composition. The partially regenerated adsorbent composition was then stirred in 0.5% H2SO4 for 15 minutes followed by filtering and washing with water to obtain a fully regenerated adsorbent composition. Washing was done till the pH of the solution became neutral. Finally the regenerated adsorbent composition was dried and reused for simultaneously reducing the anionic and cationic pollutants from waste water. The adsorbent composition of the present disclosure is regenerated up to 3 times.
Experiment 4: Treatment of waste water using regenerated asorbent composition
Same experimental procedure was followed as described in Trial 1 of Extperiment 2, except that the regenerated adsorbent composition obtained in Experiment 3 was used.
Table-2: Reduction of anionic and cationic contents from waste water using the regenerated adsorbent composition of the present disclosure.
Fluoride compounds (ppm)
(Anionic pollutants) Zinc compounds (ppm)
(Cationic pollutants) Lead compounds (ppm)
(Cationic pollutants)
Feed 15.7 55.38 39.69
Treated water 1.3 18.19 0.15
As observed from Table-2, the regenerated adsorbent composition of the present disclosure is capable of removing contaminants, such as fluoride and lead with more than 90% efficiency.
The adsorption capacity of the regenerated adsorbent composition of the present disclosure is comparable to fresh/initial adsorbent composition. The adsorption capacity of the adsorbent composition of the present disclosure for removing fluoride is summarized in Table-3.
Table-3: Adsorption capacity of the adsorbent composition of the present disclosure
Stages Adsorption Capacity (mg/g)
Initial 2.6
1st Regeneration 2.8*
2nd Regeneration 2.5
3rd Regeneration 2.4
* On regenerating the adsorbent composition for the first time, the adsorbent composition adsorption capacity increases, as more active sites are available as compared to virgin (initial) material.
It is seen from the Table-3 that the adsorption capacity of the adsorbent composition for removing fluoride after three cycles of regeneration is in the range of 2.4 mg/g to 2.8 mg/g.
Experiment 5: Treatment of waste water for reducing the content of anionic pollutants by using adsorbent composition prepared in example 1 by using a column
Waste water having anioinic content (fluoride compounds) was passed through a column (column length- 100 cm and column diameter- 4.5 cm) containing 1.2 kg of the adsorbent composition obtained in Example-1 at 30 °C, at a flow rate of 40-45 L/h. After the treatment, the treated water was analysed for fluoride contents in treated water.
The results of the treatment are summarized in Table 4.
Table-4: Reduction of anionic contents from waste water using the adsorbent composition of the present disclosure.
Feed water parameters Treated water parameters
Fluoride Conc. (ppm) pH Treated water (Liter) Fluoride Conc. (ppm) Removal (%) Adsorption (mg/g) pH
5.65 7.41 50 0 100.00 0.2354 4.22
100 0 100.00 0.2354 5.32
5.39 7.078 150 0 100.00 0.2246 5.67
200 0 100.00 0.2246 6.11
250 0 100.00 0.2246 6.32
300 0.019 99.65 0.2238 6.91
5.49 8.48 350 0.399 92.73 0.2121 6.15
400 1.23 77.60 0.1775 6.302
450 2.17 60.47 0.1383 6.69
500 2.39 56.47 0.1292 6.71
5.44 6.92 550 1.44 73.53 0.1667 6.72
600 2.52 53.68 0.1217 6.667
650 3.11 42.83 0.0971 6.84
700 3.12 42.65 0.0967 6.82
As observed from Table-4, the adsorbent composition of the present disclosure is capable of reducing the content of anionic pollutants, such as fluoride with more than 90% efficiency.
Experiment 6: Regeneration of the adsorbent composition
Same experimental procedure was followed as described in Experiment 3, except that the saturated adsorbent composition obtained from Experiment 5 was used for regeneration.
Experiment 7: Treatment of waste water using regenerated asorbent composition
Same experimental procedure was followed as described in Extperiment 5, except that the regenerated adsorbent composition obtained in Experiment 6 was used.
Table-5: Reduction of anionic contents from waste water using the regenerated adsorbent composition of the present disclosure.
Feed water parameters Treated water parameters
Fluoride Conc. (ppm) pH Treated water (Liter) Fluoride Conc. (ppm) Removal (%) Adsorption (mg/g) pH
4.66 7.54 1 0.14 96.93 0.00376 4.43
50 0.11 97.64 0.1896 4.13
5.48 9.18 100 0.193 96.48 0.22029 4.84
5.86 10.24 150 0.32 94.54 0.2308 5.74
5.98 6.58 200 0.529 91.15 0.22713 5.96
5.87 9.29 250 0.702 88.04 0.2153 5.74
5.68 6.7 300 0.313 94.49 0.224 5.98
4.2 6.42 350 0.461 89.02 0.15579 5.99
5.56 6.49 400 0.563 89.87 0.20821 5.83
5.83 6.85 450 0.771 86.78 0.21079 6.37
5.31 6.87 500 1.07 79.85 0.17667 6.48
5.44 6.72 550 1.24 77.21 0.17500 6.58
5.64 6.45 600 1.64 70.92 0.16667 6.42
5.98 6.58 650 2.21 63.04 0.15708 6.56
5.79 6.55 700 2.53 56.30 0.13583 6.55
5.48 6.92 750 2.27 58.577 0.13375 6.84
4.98 6.73 800 2.57 48.394 0.10042 6.64
5.33 6.94 850 2.97 44.278 0.09833 6.71
5.47 6.51 900 3.32 39.305 0.08958 6.67
5.95 6.78 950 3.83 35.630 0.08833 6.81
It is seen from Table-5 that the adsorbent composition of the present disclosure can be regenerated and reused multiple times without affecting its efficiency.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an adsorbent composition that:
? is capable of simultaneously reducing the content of anionic and cationic pollutants from waste water;
? has an efficiency of more than 90% for the removal of the anionic and cationic pollutants from waste water; and
? can be regenerated and reused multiple times without affecting the adsorption efficiency.
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 disclosure to achieve one or more of the desired objects or results.
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 a 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 mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments 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. ,CLAIMS:WE CLAIM:
1. An adsorbent composition for reducing the content of anionic and cationic pollutants from waste water comprising:
(a) at least one surface modified mineral selected from bentonite and attapulgite in an amount in the range of 10 to 40 wt% of the total weight of the adsorbent composition;
(b) activated bauxite in an amount in the range of 50 to 80 wt% of the total weight of the adsorbent composition; and
(c) at least one filler selected from siliceous earth and kaolin in an amount in the range of 5 to 30 wt% of the total weight of the adsorbent composition.
2. The adsorbent composition as claimed in claim 1 is characterized by having;
• a surface area in the range of 90 m2/g to 110 m2/g;
• an adsorption capacity for anions in the range of 2.0 mg/g to 2.4 mg/g;
• an adsorption capacity for cations in the range of 3.8 mg/g to 4.6 mg/g; and
• loss on ignition in the range of 5 wt% to 12 wt% of total weight of the adsorbent composition.
3. A process for preparing an adsorbent composition, said process comprising the following steps:
a. treating at least one mineral selected from bentonite and attapulgite with an mineral acid for a time period in the range of 1 hour to 20 hours to obtain a surface modified mineral;
b. separately activating bauxite at a temperature in the range of 400 to 700 ºC for a time period in the range of 1 to 5 hours to obtain an activated bauxite;
c. mixing said surface modified mineral and said activated bauxite to obtain a first mixture;
d. adding at least one filler selected from siliceous earth and kaolin to said first mixture to obtain a second mixture;
e. adding water to said second mixture to obtain a dough;
f. extruding said dough through an extruder followed by drying at a temperature in the range of 300 to 700 ºC to obtain a dried mixture; and
g. sizing said dried mixture to obtain the adsorbent composition.
4. The process as claimed in claim 3, wherein said surface modified mineral is washed before mixing with said activated bauxite.
5. The process as claimed in claim 3, wherein said mineral acid is selected from sulfuric acid and hydrochloric acid.
6. The process as claimed in claim 3, wherein the ratio of said surface modified mineral to said activated bauxite is in the range of 1:1.5 to 1:9.
7. A process for reducing the content of anionic and cationic pollutants from waste water, said process comprising:
contacting said waste water with an adsorbent composition comprising at least one surface modified mineral, activated bauxite, and a filler at a temperature in the range of 25 °C to 35 °C to obtain a treated water;
wherein the reduction in the content of anionic and cationic pollutants is greater than 90%.