Biological Removal of Zinc (II) by Fusarium solani under Different Modes of Operational Strategies: A Comparative Study

Abstract

The goal of the current batch biosorption experiment was to determine how well Fusarium solani (isolated from soil) resting cells could remove zinc (II) from aqueous solution. With an increase in pH (up to pH 5.0) and an increase in initial zinc (II) concentration of up to 500 mg/L, the specific zinc (II) removal increases. By increasing biomass content from 2.5 to 5.5 g/L, the specific zinc (II) removal remained nearly constant. The investigations also utilised resting cells from various growth stages and at an initial zinc (II) concentration of 500 mg/L, the maximum specific zinc (II) uptake (51.7 mg/g) was accomplished (36 h old). The comparison of the results revealed that cells in a growing state (63.9 mg/g) can achieve the highest selective uptake. Hence, the uptake of zinc(II) under various operational strategies was only done with growing cells. The biological uptake of zinc (II) was then done in a fed batch mode of operation using Fusarium solani growing cells. Increased volume pulse feeding (IVPF) and constant volume pulse feeding (CVPF) were used to study the fed batch process and the impacts of these operational methods on biological performance were contrasted with those of a traditional batch process. According to batch experiments, at pH 5.0 and an initial zinc (II) ion concentration of 500 mg/l, the maximum specific zinc (II) removal was 63.9 mg/g. The maximal specific zinc (II) removal in the IVPF process was determined to be 45.47 mg/g and 33.58 mg/g, but the values in the CVPF process were 33.12 mg/g and 22.59 mg/g respectively for the first and second pulse feedings in both cases. The zinc (II) uptake found in prior investigations carried out by the current authors employing the continuous mode of operation was then compared with these results. The process could be run for a longer period of time with a maximum specific zinc (II) removal of 52.8 mg/g when operating in a continuous mode which was shown to be the optimal operational strategy.