Preparation Of Macroporous Adsorption Resin Immobilized By Modified Tannin In Liquid Phase And Its Adsorption Mechanism

With the rapid development of industry in our country,environmental pollution has become an important factor that restricts the development of Chinese economic.The industrial wastewater contain many phenolic compounds was produced from oil refining,papermaking,plastics making,ceramics,and other manufactures,which has become an urgent problem to be solved.The treatment of wastewater containing phenols with macroporous adsorption resin has many advantages,such as no secondary pollution,high concentration of raw water treatment,easy regeneration,good selectivity,and not affected by inorganic ion and pH.The study of synthesizing macroporous adsorption resin and resin's adsorption properties in upgrading the wastewater with phenolic compounds can meet the needs of our country.Using macroporous adsorption resin has great significance on promoting the quantity of wastewater and provides a new way for treating wastewater containing phenols.The main contents and research results of this paper are summarized as follows:(1)Acryloyl chloride was used to modify methyl-gallate and tannin.The modified products were analyzed by FT-IR,and the results showed that the methyl-gallate and tannin were modified successfully.The optimum synthesis condition for modifying methyl-gallate is that the molar ratio of methyl-gallate to acryloyl chloride was 1.0:1.1,the amount of acid binding agent for monomer quality 15%,at 35°C with 6 h.GPC result indicated that the modified methyl-gallate can occur polymerization under the presence of an initiator.The molecular weight of the polymer is Mw(13 637),Mn(11 820),Mw/ Mn=1.15.It showed that modified methyl-gallate had good polymerizing activity.The optimum synthesis condition for modifing tannin is that the molar ratio of tannin to acryloyl chloride was 1.0:12.0,at 30°C with 3h.GPC result indicated that the modified tannin can occur polymerization under the presence of an initiator.The molecular weight of the polymer is Mw(18 985),Mn(17 133),Mw/Mn=1.10.All the above results showed that the modified tannin also had good polymerizing activity.(2)Suspension polymerization was used to prepare the modified methyl-gallate resin and tannin resin.The methylbenzene and isobutyl acetate were used as pore forming agents,and the gelatin and polyvinyl alcohol were used as dispersants.The results of FT-IR spectra showed that there were strong absorption peaks at 3000~3500 cm-1 and 1 700~1 750 cm-1 in the modified resin,while dispersant resin had no adsorption peak in the same places.These results indicated that methyl-gallate and tannin had been successfully immobilized in the macroporous adsorption resin.(3)The effect of pore forming agent and dispersing agent on the structure of the resin was studied in detail.The results showed that along with methylbenzene in the resin was reduced;the distribution of average particle size and particle size occurred to decreasing.The distribution of particle size was the smallest with the methylbenzene and isobutyl acetate ratio was 1:1,this also meant that the resin particles have the most consistent pore size.According to the above results,we known that the molar ratio of methylbenzene to isobutyl acetate is 1:1 is optimal condition.With the increasing of the proportion of polyvinyl alcohol,the average of particle size and the distribution of particle size become decrease.When the proportion of polyvinyl alcohol increased to 60%,this decreased trending began to slow down.With different synthesis conditions,the resin's average particle size changed with the range from 475 to 510 ?m,so the dispersion agent of polyvinyl alcohol and gelatin ratio control in 3:2.(4)The performance of static adsorption and dynamic adsorption of phenolic compounds on immobilized methyl-gallate macroporous resin,and immobilized tannin macroporous resin were investigated in detail.The results showed that the static adsorption capacity increased with the extension of time,and the dynamic adsorption amount increased with the phenolic initial concentration.The dynamic adsorption showed increased trend along with the decrease of the flow rate.Compared with the commercially available macroporous adsorption resin,the adsorption capacity of the resin on the phenolic resin in this study was significantly increased.According to the comparison of modified resin's adsorption properties,the main adsorption mechanism of immobilized methyl-gallate macroporous resin and immobilized tannin macroporous resin were with hydrogen bonding and hydrophobic interaction.The ethanol-water solution was a high efficient elution agent in our study.With the increasing concentration of ethanol elution efficiency and elution speed,the phenols concentration in eluent are highly increasing.