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以五水硝酸铋(Bi(NO_3)_3·5H_2O)和溴代十六烷基吡啶(CPB)为原料,通过水热法合成溴氧化铋(BiOBr)光催化剂,并在pH=3.3的条件下分别用0.01 mol/L、0.1 mol/L、0.3 mol/L NaF溶液对其进行浸泡氟化处理得新催化剂BiOBr-F_(0.01)、BiOBr-F_(0.1)和BiOBr-F_(0.3).运用XRD(X-射线衍射)、SEM(扫描电镜)、UV-Vis DRS(紫外-可见漫反射光谱)、XPS(X-射线光电子能谱)、FL(荧光光谱)等技术对催化剂的物理结构及性质进行表征并研究了其在可见光(λ≥420 nm)下对有机染料罗丹明B(Rhodamine B,RhB)的催化降解活性.结果表明,随着NaF浓度增加,催化剂的结构及性质均发生一定程度的改变.氟化使得BiOBr对RhB的矿化能力减弱;但BiOBr-F_(0.1)使RhB褪色加快.RhB在降解过程中涉及到超氧自由基(O_2~(·-))、羟基自由基(·OH)及空穴(h~+)氧化,矿化率减小归因于活性物种产量降低,BiOBr-F_(0.1)使褪色加速则是加快了RhB的脱烷基过程,使最大吸收峰快速蓝移.
Bi (BiOBr) photocatalyst was synthesized by hydrothermal method using bismuth nitrate pentahydrate (Bi (NO_3) _3 · 5H_2O) and cetylpyridinium bromide (CPB) as raw materials. Under the conditions of pH = 3.3 The catalysts BiOBr-F 0.01, BiOBr-F 0.1 and BiOBr-F 0.3 were soaked in 0.01 mol / L, 0.1 mol / L and 0.3 mol / L NaF respectively. XRD, SEM, UV-Vis DRS, XPS and FL spectrophotometry were used to characterize the structure of the catalyst. And the catalytic activity of the organic dye Rhodamine B (RhB) under visible light (λ≥420 nm) was studied. The results showed that the structure and properties of the catalyst were all changed with the increase of NaF concentration The biodegradability of BiBr to RhB was weakened by fluorination, but the BiBr-F_ (0.1) accelerated the fading of RhB.RhB involved in the degradation of superoxide radical (O_2 ~ (· -)), free hydroxyl (OH) and holes (h ~ +). The decrease of mineralization rate is attributed to the decrease of active species production. The acceleration of fading by BiOBr-F 0.1 accelerates the dealkylation of RhB, Absorption peak rapid blue shift.