Removal behavior and mechanism of silver from low concentration wastewater using cellulose aerogel modified by thiosemicarbazide

Due to the low concentration of silver in water, most of the cellulose adsorbents exhibited low removal efficiency, which greatly limited their practical applications. Herein, a cellulose aerogel modified by thiosemicarbamide (CAT) was fabricated for reducing and adsorbing silver ions from low concentration wastewater. The characterization results concluded that CAT owned a three-dimensional spongy structure with many circular microspheres and a better specific surface area (19.37 m(2) g(-1)), as well as the functional groups of CN+H and (CS)N. The static batch adsorption experiments demonstrated that CAT could reached the maximum removal percentage of 94.94% and adsorption capacity of 42.12 mg g(-1) under the initial concentration of Ag(I) was 15 mg L-1 and the pH value was 7. Meanwhile, the adsorption of Ag(I) on CAT was second-order reaction, and the Langmuir model could better fit the adsorption process. In addition, CAT exhibited wide pH values (1-9) adaptability and excellent adsorption performance for silver through electrostatic interaction, chelation, and reduction. This study probably provides a new method as well as important experimental data and theoretical reference for the removal of silver ions and other metals.

Automated summary

A cellulose aerogel modified by thiosemicarbamide (CAT) was successfully fabricated for removing and adsorbing silver ions from low concentration wastewater. CAT exhibited excellent adsorption performance with high removal percentage and capacity for silver ions, fitting a second-order reaction and showing wide adaptability to pH values.