US Patents

Gajanan Kundalik Dewkar, Vinay Vijayraj, Thakur Sanjeevani, Amrit Pardhy, Arumugam Sudalai, Sukumar Devotta, US 6825383, 30th December, 2004 - Catalytic process for regiospecific chlorination of alkanes, alkenes and arenes: The present invention provides a process for regiospecific chlorination of an aromatic or aliphatic compound with a chlorine source comprising a metal chloride and other than Cl2 and SO2Cl2 in presence of hypervalent iodine catalyst and in acidic medium.

Gajanan Kundali Dewkar, Vinay Vijayraj Thakur, Sanjeevani Amrit Pardhy, Arumugam Sudalai, Sukumar Devotta, US 6872857, 29th March 2005 : Process for conversion of phenol to hydroquinone and quinones: The present invention relates to a process for the conversion of phenol to hydroquinone and quinones. More particularly this invention relates to a process for the oxidation of phenol to a mixture of 1,4-benzoquinone and hydroquinone using an oxidant in the presence of titanium superoxide as a reusable catalyst in a liquid phase condition.

Patil Mahendra Palasram, Deshkar Ashok Mahadeorao, Deshpande Sarvottam Damodar, Chakrabarti Tapan, Devotta Sukumar, US 7338429, 4th March 2008 : Method for direct solidification and stabilization of liquid hazardous wastes containing up to 100,000 mg/L of arsenic: The present invention relates to a method for direct treatment of liquid wastes containing up to 10% or 100,000 mg/L of arsenic by solidification/stabilization in a relatively cost effective and environmentally safe. The method also permits the simultaneous utilization other heavy metal bearing wastes (such as spent catalysts), in the solidification/stabilization of liquid wastes containing very high concentration of arsenic. It also deals with a method for converting liquid wastes containing very high concentration of arsenic into a non-leachable solid residue ready for final disposal. The direct treatment of liquid wastes containing very high concentration of arsenic by solidification /stabilization will eliminate the additional stage of converting liquid wastes to solid or semi-solid form prior to solidification/stabilization, thereby significant reduction in overall cost associated with arsenic waste treatment.

Girish Ramesh Pophali, Tapas Nandy, Santosh Narain Kaul, Sukumar Devotta, US 7637379, 29thDecember 2009 : Circular secondary clarifier for wastewater treatment and an improved solids-liquid separation process thereof: The improved circular secondary clarifier of the present invention requires less surface area and low HRT and provides efficient solids-liquid separation. The improved clarifier has better SS and BOD reduction and provides high under flow solids concentrations, as compared to conventional secondary clarifiers. The improved clarifier is even capable of treating wastewaters containing low MLSS concentration. One of the biggest advantages of improved clarifier is that it does not require a separate sump cum pump house as it removes the settled sludge using suction mechanism thereby reduces capital and recurring cost. Further, it provides natural flocculation, which is essential for agglomeration of solids and increases particle size referred to as ‘floc’ and eliminates provision for a separate flocculation facility thereby reduces capital and recurring costs.

Sadhana Suresh Rayalu, Pawan Kumar, Siddharth Ulhas Meshram, Amit Kumar Bansiwal, Nitin Kumar Labhsetwar, Rishi Narayan Singh, Sukumar Devotta, US 7510659, 31st March 2009 : Surface-modified zeolite and process for synthesis thereof for sequestration of anions: 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.