Effects of adsorbent dose and size on phosphate-removal from wastewaters

Laboratory scale production of rinsed tamarind nutshell activated carbon (TNSAC) was done by the method of single stage chemical activation, with zinc chloride as an activation agent. Using this adsorbent, adsorption studies were conducted in agitated batch flow reactors with a fixed initial phosphate concentration and with varying adsorbent particle sizes and doses, The highest percentages adsorbed, for an adsorbent dose of 4 g litre(-1), were 57% and 44%, respectively, for adsorbent particle sizes of 106.1 microm and 232.4 microm. Two different models have been developed for predicting the percentage of phosphates adsorbed. Both models manifested high coefficients of correlation, indicating their robustness. The adsorption isotherms developed were observed to resemble the form of Freundlich isotherms. A generalized model has been developed for predicting the adsorptive capacity with respect to the stated test conditions. This model exhibited good coefficients of correlation.