Kinetic studies on removing phosphate from synthetic solution and river water by reactive material in a form of suspended reactive filters

摘要

The research investigates the mechanisms and the efficiency of sorption process based on the pseudo-first and pseudo-second kinetic order models describing phosphate removal by reactive material (RM) Polonite (R) implemented in the form of suspended reactive filters. An estimation of the optimal mass to volume ratio for practical use of RM in field conditions is an additional aim of this study. Two liquids were used (synthetic solution [SS] and river water [RW]) with three mass of RM to liquid volume ratios: 1 g:1 L, 5 g:1 L and 10 g:1 L. The results obtained after 30 d, better correspond to the pseudo-second kinetic order model which provides that chemisorption is the main sorption mechanism of phosphate removal. Depending on predicted results the recommended mass to volume ratio for prospective use is 1-5 g:1 L. The ratio 1 g:1 L promotes long-lasting sorption by RM and gives high unit sorption of 3.147 and 1.875 mg.g(-1) for SS and RW experiments, respectively. The ratio of 5 g:1 L favors fast phosphate removal: 94% and 64% concentration removal for SS and RW along 4 d, respectively. The studies showed that irrespective of RM mass, phosphate removal efficiency from RW was lower of around 40% comparing with SS.