Construction of porous sodium alginate/TEMPO-oxidized cellulose composite aerogel for efficient adsorption of crystal violet dye in wastewater

Abstract

Abstract Cationic dyes pose a serious threat to human health as one of the main constituents of wastewater used in printing and dyeing. It has become difficult to remove them effectively. Adsorption based on aerogel of biomass material has become an attractive way to solve this problem. Herein, three-dimensional porous aerogel (STA) was constructed innovatively by sol-gel method and freeze-drying with sodium alginate (SA) and TEMPO-oxidized cellulose (TOC) as raw materials under the dual cross-linking effect of Ca2+ and glutaraldehyde (GA). Multiple characterization approaches and analytical methods were used to study STA. The results indicated that the addition of TOC resulted in the excellent pore structure, thermal stability, charge characteristic and adsorption capacity of STA. The adsorption capacity of STA was investigated by selecting crystalline violet (CV) as a typical cationic dye. Thereafter, the adsorption capacity was comprehensively analyzed by varying temperature, pH and adsorption time. The adsorption process conformed to the pseudo-second-order kinetic model, and the Langmuir isothermal adsorption model has a better fit, which was a single-molecule layer chemisorption process. The highest adsorption capacity reached 505.96 mg/g. Moreover, STA also possessed outstanding competitive adsorption capacity and cyclic adsorption performance.