Council of Scientific and Industrial Research

Sadhana Suresh Rayalu

Purushottam Khanna

Nitin Kumar Labhasetwar

Sukumar Devotta

Pawan Kumar

Siddharth Ulhas Meshram

Amit Kumar Bansiwal

Nitin Kumar Labhsetwar

Rishi Narayan Singh

Priti Ashok Mangrulkar

Meenal Vivek Joshi

Chandan Prabhu

Renu Mahendra Singh Yadav

Present invention deals with cost-effective surface-modified zeolite materials developed from commercial zeolites and flyash-based zeolites by treating with surface modifiers like hexadecyltrimethyl ammonium bromide (HDTMA-Br). The formation of zeolitic materials with anionic characteristics requires treatment with a surfactant with initial concentrations greater than its critical micelle concentration (CMC). The sorption of oxyanions on the surfactant-modified zeolite (SMZ) is attributed to surface complexation and surface precipitation. Incorporation of metal ions on SMZ showed improved anion uptake for dearsenification of water due to synergistic effects and is able to meet the stringent target of 10 ppb of As on potable water being adopted by most countries. High selectivity, faster kinetics and high adsorption capacity ensures cost effectiveness of this product as compared to other low-cost products for dearsenification. Zeolite analogues with anionic characteristics have been developed for their applications for removal of arsenic from water. The material developed can also be used to remove other anions like chromium and selenium.

Surface-modified zeolite and process for synthesis thereof for sequestration of anions

The present invention relates to a process for the synthesis of flyash based zeolite-Y (FAZ-Y), comprising grainding and mixing of flyash with caustic soda in a ratio ranging between 1:0.4-1:1.2 to obtain a fine homogenous fusion mixture, heating the said fusion mixture in an invert vessel at about 500-600.degree. C. for about 1-2 hours to obtain a fused mass, cooling, milling, and mixing of the said fused mass in distilled water for about 8-12 hours, subjecting the said slurry to hydrothermal crystallization at about 90-110.degree. C. for 8 to 12 hours to obtain FAZ-Y crystals, washing the said crystals with water and then subjecting the washed crystals to oven drying at 50-60.degree. C. to obtain the desired FAZ-Y crystals.

Process for the synthesis of flyash based zeolite-Y

The present invention relates to a process for synthesis of flyash based Zeolite-A, said process comprising grinding and mixing of flyash and caustic soda in a ratio of 1:1.2 and optionally adding sodium aluminate or aluminium hydroxide to obtain a fine homogeneous fusion mixture; heating the said mixture in an inert vessel at about 500-600.degree. C. for about 1-2 hrs. to obtain a fused mass; cooling, milling, and mixing the said fused mass in distilled water for about 8-10 hrs. with simultaneous optional additon of sodium aluminate or alum solution, in the present or absence of NaC1 followed by optional addition of zeolite-A seeding to obtain amorphous alumino -silicate slurry; subjecting the said slurry to hydrothermal crystallisation at about 90-110.degree. C. for 2 to 4 hrs. to obtain Zeolite-A crystals; and washing the said crystals with water and then subjecting the washed crystals to oven drying at about 50-60.degree. C. to obtain the FAZ-A crystals.

Process for the synthesis of flyash based Zeolite-A

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Nagpur, India

Sadhana Suresh Rayalu