Removal of arsenic from an aqueous solution by pretreated waste tea fungal biomass
Arsenic exists in natural waters both in inorganic and organic forms. The inorganic form of arsenic is more toxic compared to its organic form. Inorganic arsenic is the predominant form in contaminated groundwater. Arsenic exists in two,oxidation states: arsenite, As (III) and arsenate, As (V) (Pokhrel and Viraraghavan, 2006). It is introduced in the aqueous system through geochemical reactions industrial waste discharge or even agricultural use of arsenical pesticides (Loukidou et al., 2003). The presence of arsenic in groundwater has been a major public health concern in many countries such as Bangladesh, India, China, Kurdistan of Iran, Argentina, Canada and USA (ATSDR, 2002 and WHO, 2001). The problem of arsenic contamination in groundwater poses is a serious threat in these areas because groundwater is the main source of drinking water (Pal et al., 2002). Long-term exposures to arsenic levels can result in permanent and severe damage to human health. Arsenic toxicity causes skin lesions, damage mucous membranes, digestive, respiratory, circulatory and nervous system (Murugesan et al., 2006). According to the European Commission as well as to the US Environmental Protection Agency, the acceptable value of As in drinking water is limited to10 μg/L from an earlier value of 50 μg/L (Loukidou et al., 2003). Removal of arsenic from contaminated water to satisfy the drinking water standard has been a challenge for water authorities. Iron oxides have been reported to be effective for metal ion removal.