Effective removal of lead (Pb) by natural biosorbent marine microalgae (Dunaliella salina) through batch experiment

This study was undertaken to investigate the biosorption of lead (Pb) by marine microalgae D. salina through batch model. The D. salina was isolated and identified by standard method and mass cultured in outdoor condition with optimum condition. The sorbent was prepared and analysed through FT-IR spectroscopy, and observed active functional groups such as alkyl halide (C-I and C–Cl), alcohol (C-O), aromatic (C = C), alkene (C = C), C≡N, alkyl (C-H) and amine (N–H) with different stretching were observed at the wavelength between 501.71 and 2897.19 cm−1. The batch experiment was conducted with several factors such as pH, contact time and sorbent dosage. In the pH experiment, the results were shown pH dependent, and the maximum Pb absorption was noticed for 4.5 mg/L at the pH of 7–8, and the lowest Pb absorption was recorded 1.1 mg/L at the pH of 12. In time duration set, the absorption was noticed time dependent, and maximum of Pb removal by contact time was noticed higher in 120 min of 3.9 mg/L and lower absorption in initial time of 30 min. The influence of sorbent dosage on Pb removal was displayed concentration dependent, the maximum removal of lead 6.1 mg/L was noticed in 10 g L−1, and the lowest removal was observed in initial dosage of 2 g L−1. In conclusion, D. salina has more metal binding functional groups and sites on surface, and also it is a cheap cost additional biosorbent for removal of metal from industrial effluents.