Abstract:
A cellulose-based intelligent composite material (Cell-Azo-TiO
2) with photo-controlled adsorption/desorption and photocatalytic degradation functions was fabricated to solve the problem of large amount of eluent used in the regeneration process, which would easily cause secondary pollution. The Cell-Azo-TiO
2 was synthesized via graft copolymerization with photo-responsive azobenzene monomer followed by nano-TiO
2 loading. The structure, morphology, and photo-responsive properties of the composite were characterized using instrumental techniques. The adsorption performance for tetracycline (TC)-Cu(Ⅱ) combined pollution was investigated, and the desorption behavior of Cu(Ⅱ) under ultraviolet light irradiation, along with the photocatalytic degradation performance of TC, were evaluated. The results showed that the azobenzene monomer was successfully grafted, and anatase TiO
2 was uniformly loaded on the cellulose matrix. The specific surface area of the material significantly increased from 29.14 m
2·g
−1 to 115.48 m
2·g
−1, forming a hierarchical pore structure with synergistic micro-mesopores. In the TC-Cu(Ⅱ) combined pollution system, the maximum adsorption capacities of the composite material for TC and Cu(Ⅱ) were 98.12 mg·g
−1 and 121.86 mg·g
−1, respectively. Under ultraviolet light irradiation, the desorption rate of Cu(Ⅱ) reached 99.06% within 120 minutes, while the photocatalytic degradation rate of TC reached 99.24%, and the mineralization rate reached 63.2%. After six adsorption-desorption-degradation cycles, the desorption rate of Cu(Ⅱ) and the degradation rate of TC still remained above 81% and 86%, respectively. Moreover, no significant changes in chemical structure, crystalline phase or the surface morphology, pore structure of the composite were observed after cycling, indicating excellent recyclability and structural stability. The material was further evaluated for the treatment of actual wastewater, showing a good practical application prospect.