Preparation Of Microporous Benzylated Wood Powder And Study On Adsorption Ability Of Microporous Benzylated Wood Powder To Copper Ions (â…¡),Lead Ions (â…¡) And Zinc Ions (â…¡)

Contamination of Heavy Metal has become one of our country and the world’s most serious environmental problems, treatment of waste water polluted by heavy metal has attracted the attention of domestic and foreign researchers. Treatment of Heavy metal pollution has become a major issue in the world in the field of environmental protection, as well as the major challenges facing China’s environmental protection cause.In this paper, a novel microporous benzylated wood power (MBWP) has been prepared from Chinese Fir through the benzylation modification reaction and hydrothermal treatment process, respectively. Moreover, structure and morphology informations of the initial wood power and the prepared MBWP were also characterized by using of IR, SEM and NMR techniques, respectively. Taking the prepared MBWP as the adsorbents, effects of the MBWP’s weight gain rate, pH value of solution, incubation time, initial concentration of the metal ions and temperature on the adsorption of Cu2+, Pb2+ and Zn2+ were investigated carefully. Contrasting MBWP as the adsorption effect of single solution of Cu2+, Pb2+ and Zn2+, and the competitive adsorption effect of a blend solution of Cu2+, Pb2+ and Zn2+. Then, exploring the adsorption-desorption efficiency of Cu2+, Pb2+ and Zn2+ for three times. At last, illuminating adsorption mechanism of MBWP for Cu2+, Pb2+ and Zn2+. The main conclusions were obtained as follows:1.After being modified by benzylation reaction, weight gain rate of the fir powder was increased with the increases of the reaction temperature and reaction time. Therefore, to Cu2+, Pb2+ and Zn2+, MBWP (weight gain rate of 35.5%) have better adsorption effect than others.2.The analysis of IR, SEM and NMR indicated that MBWP’s chemical composition through hydrothermal treatment process did not change significantly. Crystallization zone of wood fiber arranged in the original association of hydrogen undergone some changes, wood fiber wall becomes bulky, resulting in a large number of pores or holes slightly.3.Compared with the initial wood power, adsorption capacity of the MBWP resulted from wood power via modification and hydrothermal treatment has a 57% increasement for Cu2+,209% increasement for Pb2+, and 39.8% increasement for Zn2+. Similarly, compared with the benzylated wood power, adsorption capacity of the MBWP resulted from wood power via modification and hydrothermal treatment has a 79.8%increasement for Cu2+,78.4% increasement for Pb2+, and 17.7% increasement for Zn2+.4.Under the optimized experimental conditions, the best initial pH value scope of Cu2+、Pb2+ and Zn2+, respectively, for 3.0～5.0,5.0～6.0, and 5.0～6.0.5.Adsorption percentage of MBWP for Cu2+, Pb2+ and Zn2+ were increased with the increases of reaction temperature. Under the optimized experimental conditions such as pH 5.0,30 mg/L of Cu2+, Pb2+ and Zn2+,30℃,60～90 min-incubation efficiency of Cu2+, Pb2+ and Zn2+, while the weight of MBWP were 0.500 g,95% of Cu2+,88% of Pb2+,64% of Zn2+ can be removed, respectively. And Zn2+ reaches adsorption equilibrium most quickly.6.Adsorption percentage of MBWP for Cu2+, Pb2+and Zn2+ were decreased with the increases of initial concentration of the metal ions, which were increased with the increases of adsorption time. Under the optimized experimental conditions such as pH 5.0,30℃ and 60 min-incubation efficiency, with initial concentration of the metal ions changes from 10 mg/L to 30 mg/L, the adsorption percentage of MBWP for Cu2+, Pb2+and Zn2+ were increased from 90% to 95%, decreased from 91% to 88%, decreased from 89% to 64%, respectively.7.The single adsorption percentage of MBWP for Cu2+, Pb2+ and Zn2+ in descending order:Cu2+>Pb2+> Zn2+. In a blend solution of Cu2+, Pb2+ and Zn2+, the adsorption percentage of MBWP for Cu2+,Pb2+ and Zn2+ in descending order:Pb2+> Cu2+> Zn2+. In addition, the competitive adsorption percentage for Cu2+, Pb2+ and Zn2+ was lower than single metal ion adsorption ratio.8.Taking off the metal ions from MBWP with 0.1 mol/L HCL, the adsorption percentage of MBWP for Cu2+,Pb2+ and Zn2+ in descending order:Zn2+> Cu2+> Pb2+. Furthermore, adsorption percentage of MBWP for Cu2+, Pb2+and Zn2+were decreased with the grow in number of times of adsorption. In short, MBWP has the best effect of adsorption for Zn2+, and has the worst effect of adsorption for Pb2+.9.The possible adsorption mechanism of MBWP for the metal ions was that:Ion Diffusion Stage, Wood Surface Adsorption Stage, Wood Interior Pphase Adsorption and Adsorption-Desorbed Balance Stages. Adsorption of MBWP for the metal ions have separated two kinds of stages, one is fast adsorption and the other one is slow adsorption stage. The saturant adsorption quantity of metal ions in the descending order:Pb2+>Cu2+>Zn2+, respectively, that is 2.61 mg/g,2.50 mg/g and 1.89 mg/g.This paper prepared by the study of adsorption effect and mechanism of MBWP for Cu2+, Pb2+ and Zn2+, which is desirable to find a new way to use discarded wood flour processing wastewater containing heavy metal ions. This study has important guiding significance for the use of waste biomass material to handle waste water containing heavy metal ions, and has important development prospects of reducing pollution of the ecological environment and practicing "By Waste" new ideas.