![Sample our Environment & Sustainability journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5935/TOC-Subject-Sample-2021-Environment-Sustainability.jpg"})
Abstract
Cellulose surfaces were modified by phosphoric and citric acids, and the modified celluloses were used as adsorbents to remove Cu2+ ion from the aqueous solution. The modified celluloses were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and specific surface area/zeta potential analyzers. The citric acid-modified cellulose (CAMC) removed copper more efficiently than the phosphoric acid-modified cellulose (PAMC). Optimal preparation of CAMC was by heating the cellulose in 400 mL of 1.2 M citric acid at 150°C for 3 h. FTIR measurements confirmed that the formation of carboxylic groups on CAMC surface, which increased binding with Cu2+ ions. The BET surface areas were 0.30, 0.44, and 2.4 m2/g for the original cellulose, CAMC, and PAMC, respectively, with pore sizes of 64, 32, and 7.7 nm, respectively. Experimental results showed apparent second-order adsorption kinetics and Freundlich type of adsorption isotherms. The adsorption capacity of CAMC for Cu2+ ions was 15.1 mg/g; it increased with increasing pH, temperature, and adsorbent dose but decreased with increasing Cu2+ ions. Copper removal was via physisorption, and the process parameters ΔH° and ΔS° were determined at 11.9 and 116 J mol K, respectively, for CAMC.
Acknowledgment
The authors would like to thank the National Science Council of the Republic of China, Taiwan, for financially supporting this research under Contract No. NSC 101-2221-E-151-038-MY3.