Isolation and identification of Trichoderma harzianum from groundwater: An effective biosorbent for defluoridation of groundwater.

The ability of non-viable form of Trichoderma harzianum, isolated from fluoride rich groundwater, was investigated as biosorbent for defluoridation of groundwater. Biosorption experiments were carried out at laboratory scale for removal of fluoride from groundwater. Significant effect of operational parameters on fluoride biosorption using Trichoderma harzianum as biosorbent was evaluated by varying operational parameters such as: initial fluoride concentration (2-8 mgl(-1)), biosorbent dose (0.4-1.6g/100ml), groundwater pH (6-10), temperature (30-50 degrees C) and biosorption time (30-120 min). The fluoride adsorption isotherms were modeled by Langmuir and Freundlich isotherms. Our result showed that fluoride biosorption, significantly increased with increase in groundwater pH, biosorbent dose, temperature and biosorption time, whereas increase in initial fluoride concentration reduced fluoride removal. The fluoride biosorption was rapid and maximum fluoride uptake was attained with 1.6g 100ml(-1) biosorbent within 60 min. Optimal pH 10 and temperature 50 degrees C gave maximum defluoridation efficiency. Freundlich isotherm fits well for defluoridation of groundwater using Trichoderma harzianum as biosorbent which indicated that biosorbent surface sites were heterogeneous in nature and fitted into heterogeneous site binding model.