Valorisation of dried biomass of water lentils for biosorption of Pb(II) from water in up-flow continuous column mode

Abstract

The current research entailing a continuous adsorption approach in a fixed bed coulmn was accomplished to appraise the Pb(II) adsorption efficiency of dried biomass of a water lentile i.e. Lemna gibba. The study sought to understand the effect of operational parameters i.e.bed height and flow rate on the adsorption of Pb(II) by analysing the breakthrough curves. On the analysis of breakthrough curves it was observed that a reduced flow rate and higher bed depths resulted in higher adsorption efficiency. This also resulted in longer exhaustion and breakthrough times thus treating larger volumes of metal containing water before the bed gets fully saturated. The optimum operational parameters, aimed for the maximum removal 87.83 mg/g of Pb(II) from aquoeus solution containing 103.6 mg/L lead, are 19 cm bed depth and 2.0 mL/ min. The study also revealed the succesful application of Bed depth service time model with R² value greater than 0.996. Desorption experiments were conducted in order to regenerate, recycle and reuse the biosorbent for multiple cycles. Charaterisation of biosorbent before and after adsorption was done to study the surface morphology, elemental composition and crystalline phases of the biosorbent. It showed that Pb(II) was successfully adsorbed on the surface of adsorbent.