Citric acid-modified pineapple leaves (Ananas comossus) for nitrate and chloride ions removal

Abstract

Industrial developments have provided both positive and negative impacts for the environment. The environmental pollution caused by industrial activities discharge toxic waste such as chloride and nitrate. Therefore, recent research employed pineapple leaves (Ananas comossus) as a cellulose-based material to remove chloride and nitrate ion in aqueous solution. The pineapple leaf powder was modified using citric acid to enhance its performance. The optimum conditions were achieved at pH 2, contact time 90 minutes, concentration 100 mg/L for chloride removal meanwhile the removal of nitrate reached the peak at pH 3, contact time 150 minutes, and concentration 50 mg/L for pineapple leaves before modification. After citric acid modification, the optimum point was reached at pH 5, contact time 120 minutes, concentration 100 ppm for chloride. For nitrate adsorption, the optimums condition was at pH 4, contact time 150 minutes, and concentration 50 mg/L. The adsorption capacity of both adsorbents did not significantly change after three times adsorption/desorption cycles. Adsorption of pineapple leaf before and after modification followed the Langmuir isotherm model for chloride and nitrate removal. The obtained adsorbents were characterized using Fourier Transform Infra-Red (FTIR), Scanning Electron Microscopy (SEM) and Breuneur-Emmet-Teller (BET) indicating significant difference before and after adsorption onto pineapple leaves took place.