Nanocrystalline Cellulose Based on Chitosan Hydrogel Structure as a Biological Adsorbent for Effluent of Fish Culture Farms

Abstract

Natural hydrogels have replaced synthetic hydrogels due to their properties such as long life, high water absorption capacity, high strength and resistance. Recently, hydrogels have been defined as two- or multi-component systems consisting of three-dimensional networks of polymer chains that fill the space between macromolecules, and the efficiency of their water absorption depends on the polymeric nature and density of the polymer network connections. Due to climate change and frequent droughts, supply of fresh water has become one of the major barriers of sustainable aquaculture development in Iran. Therefore, wastewater treatment and reuse can be a suitable solution to meet the water requirement of expanding aquaculture industry. The purpose of the present study is to assess the efficiency of a new hydrogel prepared from agricultural waste (bagasse) in removal of nitrogen and phosphate compounds from the effluent of fish farms. First, the hydrogel was prepared during the polymerization process and then, in order to determine the optimal adsorption, it was tested in a discontinuous system by performing adsorption isotherm calculations. In cellulose/chitosan nanocrystalline hydrogel nanosorbent, the removal rates for nitrate, nitrite and phosphate were 84.3, 86 and 90.9%, respectively. Optimal adsorption were determined at acidity 6, time 30 minutes, temperature 40 ° C, concentration 100 mg / l and adsorbent weight 0.5 g. Comparison of adsorption isotherm models showed more conformity with Freundlich and Tamkin absorption models with correlation coefficients of 0.99 and 0.97 for nitrate, 0.98 and 0.91 for nitrite and 0.99 and 0.93 for phosphate, respectively.