A bioassimilation and bioaccumulation model for the removal of heavy metals from wastewater using algae: New strategy

Abstract

A mathematical model for bioassimilation (BS) combined with bioaccumulation (BC) has been conducted to determine the removal and recovery of heavy metals (HMs) from wastewater using green algae. Response Surface and Box Benken Methodology (BBM) combined with best-fit simulation were used to determine ultimate uptakes. Results revealed that the percentages of HM removal (% RE r) and recovery (%HMc) are correlated with algal growth under the studied conditions. The developed mathematical model accurately predicts the % RE and HMc based on BS and BC mechanisms. Although the biosorption process exhibited higher metals uptakes than BS, the latter had a better affinity for the removal of different metals. The combined BS and BC mechanisms achieved 73 % and 69 % of Cu2+ and Pb2+removals, respectively, with the BC process is 6 folded higher than BS. Comparable percentage removal ? 74 % was observed for Cd2+, with 99 % of the removal was based on BC. The %HMc from aqueous and solid phases out of the hydrothermal liquefaction (HTL) process was estimated at 56.5 %. Mathematical modeling of the combined BS with BC processes provides an efficient and robust tool for predicting and forecasting the performance of HMs removals and recovery via algae process.