Efficiency evaluation of Zinc and Nickel removal through coagulation and flocculation process using chitosan

Background: The release of large quantities of zinc(Zn) and nickel(Ni) into the natural environment cause some environmental problems. The aim of this research was investigation the effect of chitosan biopolymer as a natural fluctuant in order to remove Zn2+ and Ni2+ from aqueous solutions. Material and methods: Experiment in batch system as the half experiment study with change in effective parameters such as pH (6-9), dose of coagulant (10-100 mg/l), settling time and initial amount of metal was investigated. Results: Results of this study showed that Zn2+ and Ni2+ removal increases with pH increases. The optimal amount of coagulant used for this study was defined between 60 - 100 mg / l respectively. So the results of this study also showed that initial concentration of metal had inverse relation with Zn and Ni removal efficiencies in coagulation and flocculation processes. Conclusion: Due to chitosan properties such as biocompatibility, biodegradability, ability to remove heavy metals and also having amine, hydroxyl and carboxylic function groups it can be use as a coagulant and/or flocculant to remove heavy metals from aqueous solutions.