Functionalized brine sludge material and a process for the preparation thereof

Abstract

Brine sludge is an industrial waste generated in chloral alkali industry. The generated brine sludge waste is dumped into landfills and contains barium sulphate, calcium carbonate, magnesium hydroxide, sodium chloride, clay, and toxic elements like chromium, zinc, copper, and vanadium, therefore posing an environmental threat. Consequently, there is an urgent need to convert toxic brine sludge waste into its non-toxic form. The present invention thus aims to achieve total utilization of this brine sludge for making functionalized brine sludge material useful for a broad application spectrum.

Claims

1. A functionalized brine sludge material comprising: 10 g to 50 g of brine sludge; 50 g to 100 g of fly ash; 6 g to 13 g of sodium hydroxide; 250 ml to 500 ml of ethylene glycol; 1 g to 10 g of cetyl trimethyl ammonium bromide; and 12 ml to 26 ml of water.

2. The material as claimed in claim 1, wherein the material is useful for the preparation of radiation shielding materials, geopolymeric materials, and chemically designed composite materials.

3. The material as claimed in claim 1, wherein the material comprises 45 g of brine sludge, 45 g of fly ash, 6 g of sodium hydroxide, 300 ml of ethylene glycol, 10 g of cetyl trimethyl ammonium bromide, and 12 ml of water.

4. A process for the preparation of the functionalized brine sludge material as claimed in claim 1, the process comprising: (a) refluxing a homogenized mixture of brine sludge, fly ash, sodium hydroxide, ethylene glycol, cetyl trimethyl ammonium bromide, and water in a round bottom flask; and (b) filtering the mixture as obtained in step (a) followed by drying in an air oven at a temperature of 100 to 110 degrees C. for a period of 1 to 2 hours, resulting in an in-situ synthesized functionalized brine sludge material.

5. The process as claimed in claim 4, wherein refluxing in step (a) is done at a temperature of 190 to 250 degrees C. for a duration of 2 to 6 hours using conventional heating.

6. The process as claimed in claim 4, wherein refluxing in step (a) is done at a temperature of 40 to 45 degrees C. for a duration of 15 to 20 minutes using microwave heating.

7. The process as claimed in claim 4, wherein drying in step (b) is done at a temperature of 110 degrees C. for a duration of 1 to 2 hours.

Description

DETAILED DESCRIPTION

(1) The brine sludge contains a number of chemical compounds, namely barium sulphate, calcium carbonate, magnesium hydroxide, sodium chloride, toxic elements like chromium, zinc, copper, and vanadium, and clay-like materials. The presence of all these materials makes the matrix of brine sludge most non-uniform, non-homogeneous, and in segregated form. Therefore, a novel process has been developed to provide uniform, homogeneous brine sludge in non-segregated form.

(2) Homogenization of the materials is done automatically during the reaction due to simultaneous and synergistic chemical reactions among the various ions of the reactants namely brine sludge, fly ash, sodium hydroxide, ethylene glycol, cetyl trimethylammonium bromide, and water.

(3) Conversion of brine sludge from micron size to nano-size is done on its own during synthesis due to the presence of cetyl trimethyl ammonium bromide (CTAB), which acts as a powerful capping agent by converting the size of particles into nano range and also acting as a stabilizing agent.

(4) The present invention thus provides functionalized brine sludge material prepared from brine sludge waste having multiple elements which are toxic and micron sized. The in-situ synthesis process of the present invention enables the conversion of the brine sludge waste into multi-elemental, nano-sized, non-toxic, and functionalized brine sludge material after adding a few ingredients such as fly ash, CTAB, ethylene glycol, and NaOH. The developed functionalized material is useful for multifarious applications.

(5) Accordingly, the present invention provides functionalized brine sludge composite material comprising 10 g-50 g of brine sludge, 50 g-100 g of fly ash, 6 g-13 g of sodium hydroxide, 250 ml-500 ml of ethylene glycol, 1 g-10 g of cetyl trimethyl ammonium bromide, and 12 ml-26 ml of water.

(6) The physico-chemical characteristics of the developed functionalized materials are as follows. Field Emission Scanning Electron Microscope (FESEM) imaging of the material shows the size of particles up to 15 nm, which confirms the development of nano-sized functionalized brine sludge material so synthesized. Energy-Dispersive X-Ray Spectroscopy (EDXA) shows the presence of elements like Ba, C, O, Na, Mg, Al, Si, S, Cl, and Ca, which confirms the development of multi-elemental functionalized brine sludge material so synthesized. Fourier Transform Infrared Spectroscopy (FTIR) shows the presence of varying functional group like sulphate, carbonate, hydroxide, etc. in the synthesized functionalized brine sludge. X-Ray Power Diffraction (XRD) confirms the crystalline nature and presence of different phases like barium sulphate, sodium chloride, magnesium hydroxide, silica, calcium carbonate, etc. in the synthesized functionalized brine sludge material.

(7) The process for the preparation of the aforesaid functionalized material comprises together refluxing of a homogenized mixture of 10-50 g of brine sludge, 50 g-100 g of fly ash, 6 g-13 g of sodium hydroxide, 250 ml-500 ml of ethylene glycol, 1 g-10 g of Cetyl trimethyl ammonium bromide, and 12 ml-26 ml of water in a round bottom flask at a temperature ranging from 190 to 250 degrees C. for a period of 2 to 6 hours or using a microwave synthesizer at a temperature ranging from 40 to 45 degrees C. for a period of 15 to 20 minutes, thereby enabling simultaneous and synergistic chemical reactions among the various constituents of the brine sludge, fly ash, sodium hydroxide, ethylene glycol, cetyl trimethyl ammonium bromide, and water. The material thus obtained was filtered and dried in an air oven at a temperature of 100 to 110 degrees C. for a period of 1 to 2 hours resulting in multi-elemental, nano-sized, non-toxic, functionalized brine sludge material.

(8) The developed process involves total utilization of toxic brine sludge possessing required complementary constituents for making desired composite materials. It is an energy efficient process requiring low temperature for the synthesis of materials. The use of microwave heating instead of conventional heating in the present process leads to reduction in the synthesis temperature as well as time. The process obviates the need of costly chemicals as it utilizes the chemicals inherently present in brine sludge, thereby making it cost effective and economic. The invented process involves only two steps for the synthesis of functionalized brine sludge composite material.

(9) The developed functionalized brine sludge material has a broad application spectrum, e.g., for making a) radiation shielding materials, b) geopolymeric materials, and c) chemically designed composite materials.

EXAMPLES

(10) The following examples are given by way of illustration of the working of the invention in actual practice and therefore should not be construed to limit the scope of the present invention in any manner.

Example 1

(11) For making multi-elemental, nano-sized, non-toxic, and functionalized brine sludge material, refluxing of a homogenized mixture of 10 g of brine sludge, 50 g of fly ash, 6 g of sodium hydroxide, 250 ml of ethylene glycol, 1 g of cetyl trimethylammonium bromide, and 12 ml of water was done in a round bottom flask that was heated at temperature of 190 degrees C. for a period of 2 hours, and the material so obtained was further filtered and dried in an air oven at 110 degrees C. for a period of 1 hour so as to obtain the desired functionalized brine sludge material.

Example 2

(12) For making multi-elemental, nano-sized, non-toxic, and functionalized brine sludge composite material, refluxing of a homogenized mixture of 20 g of brine sludge, 70 g of fly ash, 10 g of sodium hydroxide, 400 ml of ethylene glycol, 5 g of cetyl trimethyl ammonium bromide, and 20 ml of water was done in a round bottom flask and heated at a temperature of 200 degrees C. for a period of 2 hours, and the material so obtained was filtered and dried in an air oven at 110 degrees C. for a period of 1 hour so as to obtain the desired functionalized brine sludge material.

Example 3

(13) For making multi-elemental, nano-sized, non-toxic, and functionalized brine sludge composite material, refluxing of a homogenized mixture of 40 g of brine sludge, 100 g of fly ash, 13 g of sodium hydroxide, 500 ml of ethylene glycol, 10 g of Cetyl trimethyl ammonium bromide, and 26 ml of water was done in a round bottom flask and heated at a temperature of 210 degrees C. for the period of 6 hours. The material so obtained was filtered and dried in an air oven at 110 degrees C. for a period of 1 hour so as to obtain the desired functionalized brine sludge material.

Example 4

(14) For making multi-elemental, nano-sized, non-toxic, and functionalized brine sludge composite material, refluxing of a homogenized mixture of 30 g of brine sludge, 90 g of fly ash, 10 g of sodium hydroxide, 300 ml of ethylene glycol, 3 g of cetyl trimethyl ammonium bromide, and 20 ml of water was done in a round bottom flask and heated at a temperature of 200 degrees C. for a period of 2 hours. The material so obtained was filtered and dried in an air oven at 110 degrees C. for a period of 1 hour so as to obtain the desired functionalized brine sludge material.

Example 5

(15) For making multi-elemental, nano-sized, non-toxic, and functionalized brine sludge composite material, refluxing of a homogenized mixture of 50 g of brine sludge, 50 g of fly ash, 6 g of sodium hydroxide, 250 ml of ethylene glycol, 1 g of Cetyl trimethyl ammonium bromide, and 12 ml of water was done in a round bottom flask at temperature of 220 degrees C. for a period of 2 hours, and the material so obtained was filtered and dried in an air oven at 110 degrees C. for a period of 1 hour so as to obtain the desired functionalized brine sludge material.

Example 6

(16) For making multi-elemental, nano-sized, non-toxic, and functionalized brine sludge composite material, refluxing of a homogenized mixture of 45 g of brine sludge, 45 g of fly ash, 6 g of sodium hydroxide, 300 ml of ethylene glycol, 10 g of cetyl trimethyl ammonium bromide, and 12 ml of water was done in a round bottom flask using a microwave synthesizer at a temperature of 45 degrees C. for a duration of 15 minutes. The material so obtained was filtered and dried in an air oven at 110 degrees C. for a period of 1 hour so as to obtain the desired functionalized brine sludge material.

(17) Table 1 below recites the properties/characteristics of the composite material obtained in Examples 1 to 6 and demonstrates the effect of various concentrations of raw materials and process parameters on the quality of the product obtained. The product obtained in Example 6 is most desirable.

(18) TABLE-US-00001 TABLE 1 Properties/Characteristics of the prepared functionalized brine sludge material Sl Techniques Properties/ No. used Characteristics Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 1 Field Emission It provides the Size of Size of Size of Size of Size of Size of Scanning Topographical of particles particles particles particles particles particles Electron the material i.e were Up were Up were Up were Up were Up were Up Microscope size of particles to 20 nm to 17 nm to 16 nm to 18 nm to 20 nm to 15 nm (FESEM) so synthesized. 2 Energy- It identifies the Confirms the Confirms the Confirms the Confirms the Confirms the Confirms the dispersive elemental presence of presence of presence of presence of presence of presence of X-ray composition of Ba, C, O, Na, Ba, C, O, Na, Ba, C, O, Na, Ba, C, O, Na, Ba, C, O, Na, Ba, C, O, Na, spectroscopy material. Mg, Al, Si, S, Mg, Al, Si, S, Mg, Al, Si, S, Mg, Al, Si, S, Mg, Al, Si, S, Mg, Al, Si, S, (EDXA) Cl, Ca Cl, Ca Cl, Ca Cl, Ca Cl, Ca Cl, Ca 3 X-ray It is used for Confirms the Confirms the Confirms the Confirms the Confirms the Confirms the powder phase identi- presence of presence of presence of presence of presence of presence of diffraction fication of crystalline crystalline crystalline crystalline crystalline crystalline (XRD) a crystalline nature and nature and nature and nature and nature and nature and material and different different different different different different can provide phases like phases like phases like phases of phases of phases of information BaSO.sub.4, BaSO.sub.4, BaSO.sub.4, element element element on unit cell NaCl, NaCl, NaCl, present like present. like present. like dimensions. Mg(OH).sub.2, Mg(OH).sub.2, Mg(OH).sub.2, BaSO.sub.4, BaSO.sub.4, BaSO.sub.4, SiO.sub.2 SiO.sub.2 SiO.sub.2 NaCl, NaCl, NaCl, CaCO.sub.3, CaCO.sub.3, CaCO.sub.3, Mg(OH).sub.2, Mg(OH).sub.2, Mg(OH).sub.2, Al.sub.2O.sub.3, Al.sub.2O.sub.3. Al.sub.2O.sub.3. SiO.sub.2 SiO.sub.2 SiO.sub.2 CaCO.sub.3, CaCO.sub.3, CaCO.sub.3, Al.sub.2O.sub.3. Al.sub.2O.sub.3. Al.sub.2O.sub.3. 4 Fourier It identifies It confirms the It confirms the It confirms the It confirms the It confirms the It confirms the Transform structures by presence of presence of presence of presence of presence of presence of Infra Red giving infor- varying func- varying func- varying func- varying func- varying func- varying func- Spectrometer mation about tional group tional group tional group tional group tional group tional group (FTIR) functional like sulphate, like sulphate, like sulphate, like sulphate, like sulphate, like sulphate, groups present. carbonate, carbonate, carbonate, carbonate, carbonate, carbonate, hydroxide etc. hydroxide etc. hydroxide etc. hydroxide etc. hydroxide etc. hydroxide etc.

ADVANTAGES

(19) The process enables the conversion of toxic brine sludge into non-toxic form by forming chemical linkages of toxic elements with silicon and aluminum present in fly ash. Due to the use of microwave heating the number of steps in the process, temperature of synthesis and duration are minimized. It enables the conversion of chemical compounds present in brine sludge from micron size to nano size. It enables increased chemical homogeneity among the various constituents present in brine sludge waste and other reactants. The use of cetyl trimethyl ammonium bromide (CTAB) results in effective capping necessary for the synthesis of materials in nanosizes. The process saves the cost of costly chemicals such as barium sulphate, magnesium hydroxide and calcium carbonate as the chemicals inherently present in brine sludge are utilized for the reaction. It involves only two steps for the synthesis of functionalized brine sludge material.