| This paper studied Polymer materials radiation modification by using 60Co gamma rays, synthesized functional radiation graft copolymerization materials with flocculation and heavy metal adsorption effect respectively. Process conditions of polymer materials radiation modification was mainly studied and optimized, and moreover, the excess sludge flocculation function of the synthesized flocculant was preliminarily discussed, as well as Cu2+ and Ni2+ removal of heavy metal adsorbent in aqueous and sludge.Microcrystalline cellulose-graft-Acrylamide was synthesized by 60Coγ-ray pre-irradiation method. The effects of various reaction conditions on the grafting degree and the utilization ratio of acrylamide were studied, such as pre-irradiated dose, reaction temperature, reaction time, MCC/AM mass ratio, Inhibitor mass and monomer concentration.The grafted copolymers were modified into a sort of cationic flocculant (CCPAM) by mannich reaction. The flocculation and dewatering effects of excess sludge were studied, comparing with polyacrylamide (PAM).The structures of the grafted copolymers were characterized by Fourier-Transform Infrared Spectroscopy. The highest grafting degree and utilization ratio of acrylamide were more than 65%, which was obtained at reaction time of 3h, pre-irradiated dose of 35kGy, reaction temperature of 40℃, MCC/AM mass ratio of 0.5:1, Fe(NH4)2(SO4)2·6H2O/AM mass ratio of 0.01%, and AMmonomer concentration of 5%. Sedimentation performance, filtration properties and centrifugal dewatering properties experiment results show that optimal dosing of PAM was 50mg/L, and the optimal dosing of PAM was 30mg/L, belower than the optimal dosing of PAM, and the flocculation and dewatering effects of excess sludge were better than PAM.Starch-graft-Acrylamide was synthesized by 60Coγ-ray co-irradiation method. The effects of various reaction conditions on the grafting degree and the utilization ratio of acrylamide were studied, such as co-irradiated dose, mass ratio of starch to acrylamide, inhibitor to acrylamide mass ratio and monomer concentration. The grafted copolymers were modified into another sort of cationic flocculant (CSPAM) by mannich reaction. The flocculation and dewatering effects of excess sludge conditioned by CSPAM were studied. Optimum synthesis conditions for graft copolymerization were as follows:the irradiation dose was 15kGy, the mass ratio of starch to acrylamide is 0.5:1, inhibitor to acrylamide mass ratio is 0.02%, and the acrylamide monomer concentration is 5%. The highest grafting degree was 244%, and the utilization ratio of acrylamide was 171%. The sedimentation performance, filtration properties and centrifugal dewatering properties experiment results show that optimal dosing of CSPAM was 40mg/L, the flocculation and dewatering effects of excess sludge performanced well.Glycidyl methacrylate (GMA) was grafted onto high-density polyethylene by using pre-irradiation induced graft in methanol solution. The influence of inhibitor doses, reaction time, radiation doses, monomer concentration, and reaction temperature on the grafting reaction was studied. The grafted material was converted to amine-type adsorbent by chemical modification using triethylenetetramine. The adsorbing properties of the amine-type adsorbent were also studied, and effects of various parameters on the metal uptake were investigated, such as pH, time, temperature, initial concentration et al. Results showed that in methanol reaction system the highest grafting degree was 332%, which was obtained at reaction time of 4h, pre-irradiated dose of 35kGy, reaction temperature of 40℃, inhibitor to high-density polyethylene mass ratio of 1%, and GMA monomer concentration of 20%. The synthesized amine-type adsorbent was used to adsorb copper and nickel in aqueous solution in different experiment condition. Results showed that in acid conditions, the metal uptake increases obviously with the increasing pH and the maximum adsorption capacity was reached at pH 6.0.Cu2+ absorption rates increased with increasing temperature, but the saturated adsorption capacity change little.Temperature increasing had little influence on nickel ions adsorption. The metal uptake increased with increasing Cu2+ and Ni2+ initial concentration, the highest saturated adsorption capacity were 162mg/g and 74mg/g respectively. The adsorption dynamics of Cu2+ and Ni2+ fits the secondary reaction kinetics model at the temperature of 293K,303K and 313K. The isothermal adsorption model fitting results showed that Ni2+ and Cu2+ adsorption fits Langmuir isothermal adsorption model. Cu2+ and Ni2+ adsorption performance of amino absorbent material in sludge was also preliminary discussed, based on acidification. Research showed that:by using nitric acid to acidify sludge, dissolved copper removal rate reached 90.3%, dissolved nickel removal rate reached 79.2%, when 2g/L adsorbent was added, the sludge was acidified to pH 3, and the acidification time was set to 24h. |
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