Study On The Preparation And Adsorption Properties Of Biomass-based Adsorbent

Water resource is an important natural resource on earth,and it is essential for human health.Nobody cannot live without water.However,with the development of industrial,the environment of water resources has been seriously damaged and faced enormous challenge in China.Furthermore,sustainable development strategic goal of China may be disturbed.Therefore,it is urgent of the technological innovations for solving the worldwide water pollution.To promote the development of society and human in a healthy way,it is necessary to find a method which is inexpensive,fast,efficient and eco-friendly to eliminate metal ions and dyes from wastewater.As a kind of nature polymer,lignin offers plenty of functional groups(hydroxyl,aromatic,carbonyl and carboxyl).These functional groups make it possible for lignin to participate in all kinds of chemical reactions.In a word,chemically modified lignin with plenty of functional groups can be used in removal of dyes and heavy metals from wastewater.In this work,lignin was used as the raw material,and modified by 5-sulfosalicylic acid or styrene.Then lignin modified by 5-sulfonyl salicylic acid(SSAL)and styrene-lignin graft copolymer(St-g-L)was successfully prepared and used to adsorb Pb2+,Cd2+,malachite green(MG),methylene blue(MB)from aqueous solutions.The structure of adsorbent was analyzed by SEM images,FT-IR spectra and X-ray diffraction technique.Further research was studied on the effect of adsorption parameters such as the concentration of adsorbent,initial solution pH value,adsorption temperature,adsorption time and initial concentrations of adsorbate on the adsorption properties.The results showed that when the concentration of adsorbent reached 5g/L,pH>3.5,T=45 ?,t=12 h and the initial concentrations of adsorbate reached 200mg/L,the adsorption capacity and adsorption efficiency about the adsorbent reached the maximum.When the adsorbent was SSAL,the adsorption capacity was 28.39 mg/g for Pb2+,16.42mg/g for Cd2+,35.27mg/g for MG,39.92mg/g for MB,and the adsorption efficiency were 70.99%for Pb2+,41.05%for Cd2+,88.17%for MG,99.80%for MB.when the adsorbent was St-g-L,the adsorption capacity was 26.39 mg/g for Pb2+,17.35 mg/g for Cd2+,39.97mg/g for MG,39.59mg/g for MB,and the adsorption efficiency were 65.97%for Pb2+,43.37%for Cd2+,99.93%for MG,98.97%for MB.For further explore the mechanism of experiment,the pseudo-first-order model,pseudo-second-order model,Langmuir isotherm model,Freundlich isotherm model and Temkin isotherm model were used for fitting the experimental data.The results showed that pseudo-second-order model and Langmuir isotherm model were suitable for the adsorption of Pb2+,Cd2,MG,MB.Compared with SSAL,the application of St-g-L can reduce the problem of secondary pollution and provides a new train of thought for removing waste from water.