Usage of crayfish chitosan composite modified film, prepared from exoskeleton of Procambarus clarkii, in treatment of water copper toxicity

Abstract

Freshwater crayfish species are considered to be the largest and the most valuable invertebrate of all inland water, so it can be used as an environmental indicator. This study aimed to use an extract from its exoskeleton in treatment of water copper toxicity, the most abundant heavy metal along aquatic habitats. Three different composite films were prepared from the exoskeleton of Procambarus clarkii, and used for wastewater remediation. In this study, film efficiency towards copper ions was determined and showed that the maximum removal was achieved by the third one which is incorporated by a Porogen substance, and increased with increasing contact time until reaching equilibrium where removal rate remains constant. The increase in temperature (25-55°C), reduces the efficiency of the all three films in removing copper ions, the best temperature value for removing copper ions for all three films, was 25°C. The thermodynamics and kinetics was studied for the third composite modified film, the adsorption process was exothermic and the kinetic model, pseudo second order is fitted to it. Adsorptive sites energy of the modified composite film was studied by applying two isothermal models; Langmuir and Freundlich models, Langmuir model was fitted to it.