Fabrication of gold nanoparticles by lignin reduction and its catalytic performance
Lignin in nature has a wide range of sources,being second only to cellulose in content,and is a renewable aromatic polymer with various properties.If lignin can be actively converted into a renewable resource or priced as a higher value material,its abundance in nature is highly likely to solve the problem of rapid resource depletion.Au NPs have unique catalytic activity due to their high specific surface area,active surface bonding and electronic states,and incomplete surface electronic coordination.Due to people's emphasis on the biological environment and a preference for non-toxic chemicals and safer organic solvents,the green synthesis of Au NPs is receiving increasing attention.Lignin is a natural three-dimensional network structure with various reducing functional groups,which can achieve green preparation of gold nanoparticles and prevent the aggregation of generated gold nanoparticles,maintaining their catalytic and antibacterial activities.In this study,lignin was utilized to reduce Au(Ⅲ)under solar excitation to pre-pare gold nanoparticles(Au NPs),which were used for catalytic reduction of organic pollutants.The factors including lignin mass concentration,HAuCl4 concentration,and reaction time on the particle size and morphology of Au NPs were investigated.Au NPs were characterized by the UV-vis spectroscopy,nanoparticle size analyzer,transmission electron microscope(TEM)and X-ray photoelectron spectroscopy(XPS).The results showed that Au NPs were suc-cessfully prepared using lignin as a reducing agent.The optimal preparation condition was as follows:lignin mass con-centration was 0.1 mg/mL,HAuCl4 concentration was 1.00 mmol/L,volume ratio of HAuCl4 and lignin was 4:1,illumination time was 60 min,and the average particle size of Au NPs was 32.14 nm.As typical organic pollutants,methylene blue(MB)and p-nitrophenol(4-NP)are widely present in industrial wastewater such as textile,paper-making,and printing.Due to their strong photostability and antioxidant properties,they are difficult to degrade and pose a serious threat to human health and the natural environment.Therefore,MB and 4-NP were used as organic pol-lutant models to explore the catalytic performance of Au NPs.The catalytic rate of the reaction was evaluated by calcu-lating the reaction rate constant k value using quasi first-order kinetics.The reaction rate constants of Au nanoparticles for MB and 4-NP were 0.765 8 and 0.316 6 min-1,respectively,indicating that Au nanoparticles had good catalytic reduction performance for MB and 4-NP.Au NPs/lignin prepared via lignin reducing Au(Ⅲ)to Au(0)was used for photocatalytic reduction of dye and nitro aromatic pollutants in wastewater,which not only realized high value uti-lization of lignin,but also achieved efficient removal of organic pollutants in wastewater.
国家科技期刊平台
NSTL
万方数据
维普
