An adsorbent prepared from Ziziphus mauritiana barks powder (ZMBP) is found to adsorb Chromate ions from water. The extractions conditions for the maximum removal of Chromate ions from water are optimized. 94.0% of Chromate is removed from water having 20 mg/L of Chromate ions at pH = 2, agitation time: 90 min, adsorbent dosage: 0.5 g/500mL, rpm: 250 and temp.: 30°C ± 1°C. The adsorption capacity is 18.8 mg/g. Co-ions are less interfered. Spent adsorbents can be regenerated and reused up to three cycles. The procedure is applied to polluted water/industrial effluents samples.

Bio-materials pertaining to Cassia Occidentalis plant are investigated as an adsorbent for the removal of Al 3+ ions from polluted water. By controlling extraction conditions namely, pH, adsorbent dosage, time of equilibration, rpm and temperature, 100% removal of Al (III) ions is achieved. Substantial amounts of Al 3+ ions can be removed even at low pH values. Even tenfold excess of common co-cations and many of anions (except Cland F -) do not interfere in the extraction. Thermodynamic parameters are evaluated to know the nature of adsorption. The methodology developed is applied successfully for the removal of Al 3+ ions from the industrial effluents and polluted water samples.

Biomaterials prepared from barks of Ficus benghalensis, Tamarindus indica and Acasia nilotica indica are investigated as adsorbents for the removal of methylene blue dye from waste waters using batch methods of extraction. Various physico-chemical parameters are optimized for the maximum removal of the dye. The extractions are found to be pH sensitive. Substantial adsorption is noted at high pHs. With simulated waters, 100 % removal of the dye is observed at pH 8/10 and at other optimum conditions of extraction with all the adsorbents developed. The optimum time needed for the maximum extraction of the dye is found to be in the order: Ficus benghalensis (120 min) > Tamarindus indica (90 min) > Acasia nilotica indica (30 min). The adsorption capacities of Ficus benghalensis sorbent, Tamarindus indica sorbent and Acasia nilotica indica sorbent are 50.0 mg/g, 66.7 mg/g and 100 mg/g respectively. In case of the Acasia nilotica indica sorbent, even at low pHs, substantial removal of the dye is effected. Co-anions (five fold excess) are least interfered while cations like, Ca2+, Mg2+ and Cu2+ have interfered to some extent but in no case, % removal has not come down below 90 %. It is interesting to note that Fe2+ and Zn2+ have maintained the maximum extraction synergistically. The developed procedures were successfully applied to real water samples too.

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Phoenix sylvestris seed powder (PSSP) was investigated as an adsorbent for the removal of chromium(VI) ions from water using batch extraction method. The conditions for the maximum extraction were optimized. The adsorption capacity was found to be 22.5 mg/g at pH= 2, contact time: 60 min, PSSP dosage: 0.40 g/500mL, rpm: 300 and temp.: 28 ± 2 ºC and found to be more suitable adsorbant than compared to other reported adsorbents in the literature. Co-ions even in five-fold excess were less interfered. Regeneration studies revealed that Phoenix sylvestris seed powder can be used up to three cycles. The method developed was successfully applied to polluted water/industrial effluents samples.