Application of Chitosan and Activated Carbon Nano-composite in Removal of Nitrite, Phosphate, and Ammonia From Aquaculture Wastewater

Abstract

Developing an adsorbent with natural components is one of the effective methods to reduce the amount of wastewater pollutants. Wastewater reuse can improve the quality of water prior to entering the natural environment. The aim of this study was to evaluate the efficiency of chitosan nano-composite and activated carbon adsorbent in the removal of nitrite, phosphate, and ammonia pollutants from fish farms of Aq-Qala. To prepare the adsorbents, the shrimp shells were converted to nano-chitosan. The date palm kernel was prepared and activated with oxalic acid in pyrolysis furnace by injecting nitrogen gas into activated carbon, then, the nano-composite was prepared from nano-chitosan and activated carbon. A field-laboratory study was conducted during the winter of 2018, and then, batches of synthesized nano-composite were investigated and the effects of pH, initial effluent concentration, and adsorption time were investigated. The experiments were performed in the pH range of 5-8, effluent concentration of 25-100 mg/L, and contact time of 15-90 minutes. The results showed that at optimum conditions (pH of 7, effluent concentration of 50 mg/L, and contact time of 60 minutes), the highest removal percentage and adsorption capacity for nitrite, phosphate, and ammonia contaminants were 99.98%, 99.77%, and 65.65%, and 6.65, 6.14, and 7.32 mg/g, respectively. Due to the high removal percentage (99.98%) of the chitosan and activated carbon nano-composite, the adsorbent was highly capable of removing pollutants (nitrite, phosphate, and ammonia).