Investigation of biosorption on Ceratophyllum demersum L. biomass: removal of cadmium(II) from aqueous solution

Abstract

This study aimed to investigate the effect of modified Ceratophyllum demersum on the removal of heavy metal cadmium. The effect of pH (3-8), contact time (5-240 min), biomass concentration (0.02-4 g/L) and initial concentration of metal (10-200 mg/L) on the removal of cadmium, as well as kinetic and isotherm adsorption models were studied using the batch adsorption experiments. The results showed that with an increase in pH from 3 to 8, the removal efficiency increased from 93% to 97%, then decreased to 85%. By increasing the contact time from 5 to 180 min, the removal efficiency ranged from 67% to 98% and then slightly decreased until to 240 min. Also, increased adsorbent dosage from 0.02 to 4 g/L, the removal efficiency increased from 37% to 99%. The removal efficiency decreased from 96% to 31% with an increase in the initial concentration of cadmium from 10 to 200 mg/L. Optimum condition was found to be at pH, contact time, biomass concentration and cadmium concentration of 7, 60 min, 1 g/L and 10 mg/L, respectively. Pseudo-second-order kinetic and Langmuir model (R 2 > 0.99) were well fitted to the data. The results of study confirmed the high ability of biosorption process through Ceratophyllum demersum for wastewater treatment polluted with cadmium.