Sorption Of Phosphate From Wastewater Using Termite Soil

Abstract

Wastewater which contains pollutants like phosphate above its permissible level and released into environment without treatment is a headache of our world today. So, the aim of this study was to investigate phosphate (P) removal efficiency of Termite mounds which is locally available, low cost adsorbent under batch experimental study. Various parameters studied including contact time, adsorbent dosage, pH, initial concentration, shaking speed, particle size, temperature and the presence of competing anions were considered. The result of this study showed that the optimum contact time for adsorption of P on termite mounds reached to equilibrium after 60 min with removal efficiency of ~96%, at optimum adsorbent dose of 10 g/l, optimum pH ~7, equilibrium initial concentration of 3 mg/L, equilibrium shaking speed 200 rpm and grain size <0.075 mm. And also, the increases of temperature also increase the removal efficiency of adsorbent. The sorption kinetics was found to follow pseudo-second-order modelR2 = 0.997 rate and the experimental equilibrium sorption data fitted well to Langmuir model with R2 = 0.978 the equilibrium adsorption, giving a sorption capacity of 4.32 mg/g for central part of termite mounds. The presences of competing anions (carbonate and bicarbonate) significantly influence P adsorption efficiency while sulfate, chloride and nitrate were interfering slightly. The adsorbent was reduced P concentration of real wastewater from 9.03 mg/L to 0.97 mg/L which was below its permissible limits. Regenerablity of adsorbent was tested using NaOH solution and the readsorption efficiency after third adsorption/desorption was >73%. From the results of this study it is concluded that the application of TMs for adsorptive removal of P is highly favorable and a spontaneous process. Therefore, it can be likely that termite mound (TM) can be used as a low cost locally available together with highly efficient adsorbent for removal of P from wastewater