磁性粉煤灰/聚丙烯酰胺复合材料的制备及其对亚甲基蓝的吸附

Preparation of magnetic MFA-PAM composite and MB adsorption

用γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)对粉煤灰进行了干法表面改性;并采用一锅水热法负载Fe_(3)O_(4)到改性粉煤灰上;然后以过硫酸铵为引发剂,以水和乙醇混合溶液作为反应相,将丙烯酰胺单体接枝聚合到Fe_(3)O_(4)/粉煤灰颗粒表面制成了磁性粉煤灰/聚丙烯酰胺复合物(MFA-PAM)。采用红外光谱、热重、X射线衍射、振动样品磁强计、扫描电镜等手段对其进行了表征。结果表明:每步所采用的方法可以将所需要的物质负载到粉煤灰表面,最后实现了丙烯酰胺对粉煤灰的良好包覆。采用紫外-可见分光光度法研究了MFA-PAM对亚甲基蓝的吸附行为。研究发现,常温下0.12g MFA-PAM对25mL 6mg/L亚甲基蓝溶液的脱色率在10min时即可达到77.6%,在120min时对亚甲基蓝的吸附率达到90.3%。另外,MFA-PAM对亚甲基蓝的吸附率在pH<8时随pH的增大而减小,在pH>8时随pH的增大而增大。

Firstly,the dry surface modification of fly ash(FA)was carried out withγ-methylacrylloxy propyl trimethoxysilane(KH570).Then a pot of hydrothermal loading of Fe_(3)O_(4) onto the surface of modified FA was used.Finally,using ammonium persulfate as initiator and mixed solution of water and ethanol as reaction phase,the acrylamide monomer was successfully grafted and polymerized onto the surface of Fe_(3)O_(4)/FA particles to prepare magnetic fly ash/polyacrylamide composite(MFA-PAM),which was applied to the adsorption of methylene blue(MB).The resulted composite particles were characterized by FT-IR,TGA,XRD,VSM and SEM.The results shown that the target functional group can be successfully grafted on to FA.The composite particles were well wrapped by PAM.Adsorption behavior of MB in aqueous solution by MFA-PAM was studied by UV-Vis spectrophotometry.It was found that,decolourization ratio of 25ml MB solution(6mg/L)with 0.12g MFA-PAM reached 77.6%with in 10minutes and reached 90.3%with in 120minutes.In addition,the adsorption efficiency of MFA-PAM decreased with increasing pH value when pH<8,and increased with increasing pH value when pH>8.