光谱学与光谱分析
光譜學與光譜分析
광보학여광보분석
SPECTROSCOPY AND SPECTRAL ANALYSIS
2014年
8期
2157-2161
,共5页
刘霞%李彦周%甘强%冯长根
劉霞%李彥週%甘彊%馮長根
류하%리언주%감강%풍장근
磷钨酸%MC M-4 8%光催化降解%吡虫啉%百草枯
燐鎢痠%MC M-4 8%光催化降解%吡蟲啉%百草枯
린오산%MC M-4 8%광최화강해%필충람%백초고
Phosphotungstic acid%MCM-48%Photocatalytic degradation%Imidacloprid%Paraquat
以介孔分子筛 MCM-48为载体，采用水热法制备了负载磷钨酸 H3 PW12 O40（HPW）的多金属氧酸盐催化剂 HPW/MCM-48。利用傅里叶变换红外光谱（FT-IR）、小角度X射线粉末衍射（XRD）、氮气吸附检测和高分辨透射电子显微镜（HRTEM）对其结构进行了表征，并以农药吡虫啉和百草枯为对象，考察了所制备的 HPW/MCM-48的光催化降解活性。结果表明，采用水热法制备的催化剂保持了 MCM-48的介孔分子筛结构和 HPW的Keggin结构，比表面积783．35 m2·g-1，孔体积1．46 cm3·g-1，平均孔径2．76 nm，相比于母体 HPW，HPW/MCM-48的比表面积大大增加；在365 nm紫外光下反应14h后，20 mg剂量HPW/MCM-48催化剂能使50 mL，10 mg·L-1吡虫啉和百草枯的降解率分别达57．38％和63．79％，而 HPW对两种农药的降解率在25％左右，空白组降解率均低于5％，说明负载后 HPW对两农药的降解活性显著增强。动力学考察表明，HPW/MCM-48对农药降解过程符合一级动力学方程，对吡虫啉和百草枯这两种农药的降解速率常数Ka 分别为0．089和0．117 h，半衰期t1/2为7．8和5．9 h。
以介孔分子篩 MCM-48為載體，採用水熱法製備瞭負載燐鎢痠 H3 PW12 O40（HPW）的多金屬氧痠鹽催化劑 HPW/MCM-48。利用傅裏葉變換紅外光譜（FT-IR）、小角度X射線粉末衍射（XRD）、氮氣吸附檢測和高分辨透射電子顯微鏡（HRTEM）對其結構進行瞭錶徵，併以農藥吡蟲啉和百草枯為對象，攷察瞭所製備的 HPW/MCM-48的光催化降解活性。結果錶明，採用水熱法製備的催化劑保持瞭 MCM-48的介孔分子篩結構和 HPW的Keggin結構，比錶麵積783．35 m2·g-1，孔體積1．46 cm3·g-1，平均孔徑2．76 nm，相比于母體 HPW，HPW/MCM-48的比錶麵積大大增加；在365 nm紫外光下反應14h後，20 mg劑量HPW/MCM-48催化劑能使50 mL，10 mg·L-1吡蟲啉和百草枯的降解率分彆達57．38％和63．79％，而 HPW對兩種農藥的降解率在25％左右，空白組降解率均低于5％，說明負載後 HPW對兩農藥的降解活性顯著增彊。動力學攷察錶明，HPW/MCM-48對農藥降解過程符閤一級動力學方程，對吡蟲啉和百草枯這兩種農藥的降解速率常數Ka 分彆為0．089和0．117 h，半衰期t1/2為7．8和5．9 h。
이개공분자사 MCM-48위재체，채용수열법제비료부재린오산 H3 PW12 O40（HPW）적다금속양산염최화제 HPW/MCM-48。이용부리협변환홍외광보（FT-IR）、소각도X사선분말연사（XRD）、담기흡부검측화고분변투사전자현미경（HRTEM）대기결구진행료표정，병이농약필충람화백초고위대상，고찰료소제비적 HPW/MCM-48적광최화강해활성。결과표명，채용수열법제비적최화제보지료 MCM-48적개공분자사결구화 HPW적Keggin결구，비표면적783．35 m2·g-1，공체적1．46 cm3·g-1，평균공경2．76 nm，상비우모체 HPW，HPW/MCM-48적비표면적대대증가；재365 nm자외광하반응14h후，20 mg제량HPW/MCM-48최화제능사50 mL，10 mg·L-1필충람화백초고적강해솔분별체57．38％화63．79％，이 HPW대량충농약적강해솔재25％좌우，공백조강해솔균저우5％，설명부재후 HPW대량농약적강해활성현저증강。동역학고찰표명，HPW/MCM-48대농약강해과정부합일급동역학방정，대필충람화백초고저량충농약적강해속솔상수Ka 분별위0．089화0．117 h，반쇠기t1/2위7．8화5．9 h。
A composite catalyst H3 PW12 O40/MCM-48 was prepared by loading photocatalyst phosphotungstic acid H3 PW12 O40 (HPW)to molecular sieve MCM-48 by impregnation method,and its structure was character-ized by Fourier transform infrared (FT-IR)spectra,small angle X-ray diffraction (XRD)patterns,nitrogen adsorption analysis and High-resolution transmission electron microscopy (HRTEM)analysis.Photocatalytic degradation activities of HPW/MCM-48 against pesticides imidacloprid and paraquat were evaluated under UV radiation (365 nm).The results show that HPW/MCM-48 maintains the mesoprous molecular sieve structure of MCM-48 and the Keggin structure of HPW,while the BET surface area is 793. 35 m2 ·g-1 ,pore volume is 1. 46 cm3 ·g-1 ,average pore diameter is 2. 76 nm,suggesting loading HPW on MCM-48 is a considerable way to improve its surface area.After 14 h UV irradiation (365 nm),57. 38% imidacloprid and 63. 79% paraquat were degraded by 20 mg HPW/MCM-48 catalyst,while HPW and blank group degraded the two pesticides at the degradation rate of about 25% and 5%,respectively.Implying loading on MCM-48 could greaterly im-prove the degradation activity of HPW.The reslut of degradation kinetics show that,the degradation process of HPW/MCM-48 fits first order kinetics equation.The rate constant Ka of HPW/MCM-48 toward imidaclo-prid and paraquat are 0. 089 h and 0. 117 h,with the half-life t1/2 of 7. 8 h and 5. 9 h,respectively.
