Preparation Of Lignin-based Polymer And Its Adsorption Properties

Lignin sulfonate (LS) is a byproduct of the paper industry, rich in resources,which contains a number of aromatic structure and hydroxyl molecules, sulfonic acid groups and methoxyl groups. LS could be modified to adsorb metal ions or organic in water. However, at present, the modified method is complex, and the adsorption effect needs to be improved. In this paper, based on the preliminary work of the laboratory, a kind of adsorption material whose preparation method is simple was prepared, and could be used to adsorb heavy metal ions and organic dyes.1. Two kinds of sodium lignin sulphonate crosslinked polymer (EPLS and SPLS) were prepared successfully via inverse emulsion polymerization and solution polymerization using sodium lignin sulphonate as a raw material, and epoxy chloropropane as a corsslinking agent; The effects of reverse emulsion polymerization temperature, amount of crosslinking agent, reaction time, emulsifier amount and different W/O system on the preparation of EPLS were studied. The yield of EPLS was 25%. The effects of different kinds of solvent system on the crosslinking polymerization reaction was studied. The results show that the yield in water-acetone and water-THF system were 25.9% and 31%. Then, their structure were characterized by IR, SEM and TGA.2. The studies on adsorption capacity of EPLS and SPLS to methylene blue (MB) were carried out. Results showed that the adsorption properties were affected by pH, temperature, initial concentration of MB and adsorption time. In range of pH 2-6, the adsorption capacity (Qe) increased with the increase of pH, and then kept unchanged basically over pH 6. The optimal adsorption temperature was at 35℃, and Qe would decreased obviously when temperature was over 35℃.At a dosage of 0.5gL-1,25℃,pH 6.5, the saturated adsorption amount of MB on EPLS and SPLS were 315.9 mg·g=1 and 321.5mg·g-1 respectively,and the adsorption efficiency was 96.8% and 93.8% respectively. The equilibrium data fitted the Langmuir isotherm and the adsorption kinetics data followed the pseudo-second-order model.3. The studies on adsorption capacity of EPLS and SPLS to Pb(II) and Cd(II) were carried out. Results showed that the adsorption properties were affected by pH, temperature, initial concentration and adsorption time. Also,competitive adsorption was existed in the mixed metal ion solution and the adsorption of Pb (Ⅱ), Cd (II) on EPLS and SPLS had a certain order. The adsorption capacity of Pb (II), Cd (Ⅱ) was increased with the increase of pH. The optimal adsorption temperature of Pb (II) was at 25 ℃. But, the adsorption capacity of Cd (Ⅱ) was increased with the increase of temperature.The Qe was increased with the increase of initial concentration. At a dosage of 1g·L-1;,25℃ the saturated adsorption amount of Pb(II) on EPLS and SPLS were 99.93 mgg-1 and 102.3mg·g-1; The saturated adsorption amount of Cd(II) on EPLS and SPLS were 55.08 mg·g-1 and 55.45mg·g-1 respectively.The equilibrium data fitted the Langmuir isotherm and the adsorption kinetics data followed the pseudo-second-order model.