%0 Journal Article
%T Two-Phase Dechlorination/Detoxification of Lindane (Hexachlorocyclohexane)
%A Abdul Ghaffar
%A Masaaki Tabata
%A Azhar Mashiatullah
%J Advances in Environmental Chemistry
%D 2014
%R 10.1155/2014/792680
%X Dechlorination of lindane was carried out in a two-phase reaction. In first phase DevardaˇŻs alloy and sodium borohydride were used in aqueous/ethanol reaction media. The reaction duration and temperature were optimized. In first phase higher dechlorination (78%) was achieved at 80ˇăC with 40-minute reaction time and the products were chlorobenzene, dichlorobenzene, and chlorocyclohexane. In second phase, Ca(OH)2 and sulfur were added in reaction media. The reactions conditions like temperature and reaction time were optimized. After 30 minutes, dechlorination was enhanced from 78% to 94% and the final products were benzene, phenol, catechol, benzenethiol, cyclohexane, cyclohexanol, and cyclohexanethiol. The results suggested that dechlorination of lindane in first and second phase was carried out through hydrodechlorination and substitution reactions, respectively. The developed method was applied for lindane containing real wastewater and higher dechlorination (91%) was achieved under optimized reaction conditions. 1. Introduction Hexachlorocyclohexane (HCH) (also called lindane), the effective component of technical insecticide HCH, had been widely used in agriculture in the mixture of technical HCH or in pure lindane throughout the world since the 1940s. It is estimated that around 10 million tons technical HCH were used between 1947 and 1997 [1]. In 2009, the use of lindane was completely banned by Stockholm Convention on Persistent Organic Pollutants [2] due to its proven adverse effect on human and other animals health and the serious environmental problems. But lindane has been used in Pakistan and is currently being used for seed treatment in Canada and the United States [3]. In addition, there are tons of HCH produced over the past and are still stored in containers waiting for being disposed of [4]. Pakistan mainly is an insecticide consumer country; the OCPs (organochlorine pesticides) were previously extensively used in the cotton production and other agricultural activities and the use of pesticide has increased by 11 to 69% in the last 20 years [5]. On the other hand at least three thousand metric tons of obsolete and expired pesticides have been stored under extreme hazardous conditions in more than thousand sites. Locally banned or severely restricted pesticides are easily available and are continuously illegally imported in Pakistan [6¨C8]. It is desirable to develop remediation technologies to clean up soil, water, and waste sites contaminated by lindane and to help speed up disposal of HCH products. Few methods like incineration,
%U http://www.hindawi.com/journals/aec/2014/792680/