Residues as Bioadsorbents for Wastewater Treatment

Conventional methods for treating wastewater containing dyes, aromatic compounds, or heavy metals are coagulation, flocculation, reverse osmosis, nanofiltration and pervaporation (Paul and Ohlrogge, 1998), and activated carbon adsorption, the latter of which is combined with membrane processes like nanofiltration (Eilers and Melin, 1999) or ultrafiltra-tion (Lenggenhager and Lyndon, 1997). 

Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, and so on were calculated. It was found that the adsorption capacity and adsorption rate constant were increased and the minimum column bed depth required was reduced when the rice husk is treated with phosphate, when compared with that of RRH. 

While cassava is an important crop across a wide range of tropical environment, cassava peels are an agricultural waste from the foodprocessing industry. Activated carbon prepared from cassava peel was used as an adsorbent in removal of dyes and metal ions from aqueous solutions. The material impregnated with H3PO4 showed higher efficiency than the heat-treated material (Rajeshvarisivaraj et ah, 2001). 

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