A new magnetic bio-sorbent for arsenate removal from the contaminated water: Characterization, isotherms, and kinetics

Arsenic (AS) is a heavy metal pollutant in water that has been known as one of the most important environmental contaminants due to its serious effects on both human health and the environment. This study was conducted to investigate the efficiency of calcined Co/Fe/Al LDH@Fe3O4@PA as a new magnetic bio-sorbent for AS removal from the polluted water.

At first, magnetic ternary calcined layered double hydroxide (Co/Fe/Al LDH) was synthesized through co-precipitation procedure. The synthesized CLDH was modified with phenylalanine amino acid, named CLDH@Fe3O4@PA. Infrared spectroscopy, X-ray diffraction, transmission, and field emission scanning electron microscopy (FESEM) were used to confirm the synthesis of the sorbent. The removal time, pH, and the sorbent dose were studied and optimized as the effective parameters on the As (V) removal.

The XRD, FTIR, TEM, SEM, EDS, and VSM techniques confirmed the properties of the synthesized magnetic bio-sorbent. Based on the optimization study, pH=6, the sorbent concentration of 30 mg, and the removal time of 5 minutes were considered as the optimum conditions with about 91% AS removal. The Langmuir isotherm with higher R2 value was matched well with the obtained results, and values obtained for qm and RL were 167 mg g–1 and 0.976 to 0.993, respectively. The kinetics studies were fitted well with the linear pseudo-first-order model with higher R2 at sorption process.

The real samples results confirmed the excellent As (V) sorption capacity of the synthesized magnetic bio-sorbent in comparison with other sorbents. Therefore, CLDH@Fe3O4@PA sorbent is introduced as a new suitable sorbent for removal of As (V) from the polluted water.