H2SO4改性TiO2光催化处理钻井废水

通过H₂SO₄改性制备了TiO₂光催化剂,采用XRD和激光粒度仪进行表征,研究了H₂SO₄浸泡浓度、光照时间、pH和氧化剂H₂O₂用量对钻井废水进行光催化处理的影响。结果表明,H₂SO₄改性并未改变TiO₂晶体结构,在钻井废水水样pH=6、H₂SO₄改性TiO₂用量15 g·L^-1、光照时间30 min和氧化剂H₂O₂用量1.0 mL条件下,钻井废水的COD值降为2 mg·L^-1,符合国家污水排放标准。     

臭氧光催化氧化工艺处理工业废水的对比研究

在pH=3、H₂O₂与硝基酚类化合物物质的量比为3∶1、Fe(Ⅲ)与硝基酚类化合物物质的量比为0.1∶1的条件下，以特征污染物硝基酚类化合物的降解率及TOC去除率为评价指标，对比了UV/O₃、UV/O₃/H₂O₂、UV/O₃/Fe(Ⅲ)3种臭氧光催化氧化工艺处理DDNP生产废水的效果。实验结果表明，反应时间1 h时经3种工艺处理后的DDNP生产废水出水的色度和TOC均可达到《兵器工业水污染物排放标准火工药剂》(GB 14470.2—2002)排放标准；UV/O₃体系中H₂O₂或Fe(Ⅲ)的加入对硝基酚类化合物的降解影响不大，而对TOC去除率具有明显的提升。实验条件下UV/O₃/Fe(Ⅲ)工艺的处理效果最优，反应时间1 h时其出水无色，TOC去除率为96%,m(BOD₅)/m(COD)由0.06提升到0.46，且出水硝基酚类化合...     

内循环式铁碳微电解/H2O2耦合工艺处理多晶硅有机废水

针对铁碳微电解反应中填料易板结及处理效率低等问题,通过增加内循环装置改进反应器结构,同时将铁碳微电解与H₂O₂进行工艺耦合,用于处理多晶硅有机废水,考察了Fe-C投加量、初始pH值、H₂O₂投加量、反应时间等工艺条件对COD去除率的影响,并通过响应面法优化了工艺条件。结果表明,各工艺条件对多晶硅有机废水COD去除效果的影响大小为：铁碳投加量>反应时间>H₂O₂投加量>初始pH值,其最适宜工艺条件为：铁碳投加量250 g·L^-1,初始pH值2.8,H₂O₂投加量112 mL·L^-1,反应时间83 min,该反应条件下COD的去除率为71.26%。铁碳/H₂O₂降解多晶硅有机废水COD的动力学回归方程为Y=0.5273X-0.6347,降解COD的速率常数为0.527 3 min^-1。     

臭氧催化氧化深度处理造纸废水的试验研究

广东东莞某一家造纸企业污水处理系统的生化池出水具有色度高、难降解的特点。采用臭氧催化氧化工艺深度处理该废水,探究了空速、臭氧投加量以及O₃、H₂O₂物质的量比对COD去除率的影响。通过试验优选出空速为7 h^-1,臭氧投加量为70 g/t,O₃、H₂O₂物质的量比为0.5时,出水COD满足GB 18918-2002一级A的要求,为臭氧催化氧化在造纸废水中的应用提供技术支撑。     

混凝-O3/H2O2氧化联合工艺处理工业塑料生产废水的研究

针对塑料生产废水成分复杂、色度高等特点,采用混凝-O₃/H₂O₂氧化联合工艺处理,工业塑料废水混凝沉淀分离后,在温度25℃、pH 7、双氧水0.6 mL/L、臭氧(O₃)浓度17.28 mg/L条件下氧化反应30 min,出水COD_Cr为20.49 mg/L,满足工业塑料废水的排放要求,为塑料制造业生产废水降解提供了新的技术手段。     

Fe2+/H2O2体系降解MB机制及影响因素研究

以亚甲基蓝（MB）作为目标污染物，实验研究了Fe²⁺/H₂O₂体系降解MB的活性物质，明确了主要反应条件对MB降解的影响特性。结果表明：HO₂?没有直接降解MB的能力；Fe²⁺/H₂O₂体系对MB的降解能力主要来自于?OH；Fe²⁺/H₂O₂体系降解MB可分为快速反应阶段和匀速反应阶段。快速反应阶段的MB降解率随温度升高而下降。体系对MB降解能力随H₂O₂初始浓度增加呈现先升高后减弱的趋势，本实验条件下，最佳H₂O₂初始浓度为5 mmol·L^-1。体系对MB降解能力随Fe²⁺初始浓度的增加而单调增加。MB降解速率随MB初始浓度的增加而增加，但MB降解率随其初始浓度呈现先增大后减小的趋势。保证?OH生成速率及其有效利用是提高体系氧化能力及H₂O₂利用率的关键。     

不同物相TiO2对H2O2/O3氧化效能的影响

研究了不同物相TiO₂对H₂O₂/O₃氧化效能的影响,目标有机物为羟基自由基探针化合物乙酸。结果表明,在初始pH为7.0和10.0时,加入TiO₂反而降低了H₂O₂/O₃的氧化效率,其中锐钛矿TiO₂比金红石TiO₂的减弱作用更为明显。当初始pH为3.0时,金红石TiO₂能显著提高H₂O₂/O₃的氧化效率,但锐钛矿TiO₂影响不明显。机理分析表明,H₂O₂浓度及其衰减速率与乙酸的去除效率有很大的相关性。在pH为7.0和10.0时,两种物相TiO₂均能加快H₂O₂的分解,其中锐钛矿TiO₂作用更为显著。此条件下HO₂^-能有效引发臭氧分解产生羟基自由基,故H₂O₂过快分解反而降低了乙酸的去除效果。在pH为3.0时,H₂O₂去质子化反应困难,故O₃/H₂O₂氧化效率极低,H₂O₂浓度也几乎不变。加入TiO₂能明显提高H₂O₂的分解速率,相比金红石TiO₂,锐钛矿TiO₂使H₂O₂在5 min内基本分解完毕,但其对H₂O₂/O₃氧化效率几乎没有影响。饱和臭氧水分解速度的批处理实验也有相似的结果。由此可见,合适引发剂浓度可能是保证臭氧类高级氧化技术较高效率的关键,否则只会导致氧化剂的无效过快分解。利用氯化硝基四氮唑蓝法对比分析了酸性条件下H₂O₂/O₃、锐钛矿TiO₂/H₂O₂/O₃和金红石TiO₂/H₂O₂/O₃体系产生超氧自由基(·O₂^-)的量,其大小顺序为:H₂O₂/O₃< 金红石TiO₂/H₂O₂/O₃< 锐钛矿TiO₂/H₂O₂/O₃,这与前面结果吻合很好。     

太阳光/TiO2-γ-Al2O3光催化处理垃圾渗滤液的研究

采用液相共沉淀法制备了TiO₂-γ-Al₂O₃复合催化剂,在其最佳合成条件下,比较了太阳光/TiO₂-γ-Al₂O₃与UV/TiO₂处理垃圾渗滤液的性能。结果表明,当Ti（SO₄）₂与Al₂（SO₄）₃·18H₂O摩尔配比为1:2、聚乙二醇2000投加质量分数为1.25%、焙烧温度为650℃时,TiO₂-γ-Al₂O₃的催化活性最强。当催化剂投加量与垃圾渗滤液COD质量比为1.75、反应时间为90 min、渗滤液pH为3时,太阳光/TiO₂-γ-Al₂O₃对COD、NH₄⁺-N的去除率几乎达到最高,分别为81.97%和54.95%,...     

臭氧催化氧化降解煤焦化高盐废水有机物的试验研究

为实现臭氧催化氧化高效去除煤焦化高盐废水中的有机物，分别采用浸渍法、混合法、喷涂法制备Fe-Al₂O₃催化剂，开展工艺优化试验以确定最优工艺参数，并对臭氧催化剂开展连续效果评价。结果表明：采用浸渍法制备的Fe-Al₂O₃催化剂对COD去除率最高，活性组分Fe₂O₃均匀负载于载体表面，粒径以30～40 nm居多；该催化剂比表面积为231.699 m²/g，孔容为0.414 cm³/g，介孔约占90%。臭氧催化氧化降解煤焦化高盐废水的最佳工艺参数为：催化剂投加量800 mg/L，臭氧质量浓度200 mg/L，臭氧通气量1.5 L/min，在此条件下连续运行100 h,COD的去除率稳定在51%～54%，该Fe-Al₂O₃催化剂具有良好的催化稳定性。     

无定形态H3PW12O40/TiO2光催化剂降解有机染料

以钛酸丁酯和磷钨酸为主要原料,采用溶胶-凝胶法制备H₃PW₁₂O₄₀/TiO₂光催化剂,采用红外光谱、X射线衍射、热重分析和比表面分析对光催化剂进行表征。结果表明,H₃PW₁₂O₄₀/TiO₂光催化剂为无定形态,比表面积202 m²·g^-1,杂多阴离子保持了Keggin骨架结构。在TiO₂中掺杂H₃PW₁₂O₄₀,使催化剂的光响应范围扩展到可见光区,从而提高光催化活性。光催化剂对甲基橙、酸性红、罗丹明B和亚甲基蓝均有较好的光催化降解活性,催化剂易于分离,重复使用稳定性较好。对甲基橙降解的适宜条件为：1.7×10-5 mol·L^-1甲基橙溶液50 mL,H₃PW₁₂O₄₀/TiO2光催化剂用量0.03 g,500 W碘钨灯照射60 min,此条件下,甲基橙脱色率可达到96%。     

The kinetics of phenol decomposition under UV irradiation with and without H2O2 on TiO2, Fe–TiO2 and Fe–C–TiO2 photocatalysts

H₂O₂ used in the photo-Fenton reaction with iron catalyst can accelerate the oxidation of Fe²⁺ to Fe³⁺ under UV irradiation and in the dark (in the so called dark Fenton process). It was proved that conversion of phenol under UV irradiation in the presence of H₂O₂ predominantly produces highly hydrophilic products and catechol, which can accelerate the rate of phenol decomposition. However, while H₂O₂ under UV irradiation could decompose phenol to highly hydrophilic products and dihydroxybenzenes in a very short time, complete mineralization proceeded rather slowly. When H₂O₂ is used for phenol decomposition in the presence of TiO₂ and Fe–TiO₂, decrease of OH radicals formed on the surface of TiO₂ and Fe–TiO₂ has been observed and photodecomposition of phenol is slowed down. In case of phenol decomposition under UV irradiation on Fe–C–TiO₂ photocatalyst in the presence of H₂O₂, marked acceleration of the decomposition rate is observed due to the photo-Fenton reactions: Fe²⁺ is likely oxidized to Fe³⁺, which is then efficiently recycled to Fe²⁺ by the intermediate products formed during phenol decomposition, such as hydroquinone (HQ) and catechol.     

Influence of operating parameters on photocatalytic degradation of phenol in UV/TiO2 process

The use of hydrogen peroxide (H₂O₂) for improved photocatalytic degradation of phenol in aqueous suspension of commercial TiO₂ powders (Degussa P-25) was investigated. Photodegradation was compared using direct photolysis (UV alone), H₂O₂/UV, TiO₂/UV, and H₂O₂/TiO₂/UV processes in a batch reactor with high-pressure mercury lamp irradiation. The effects of operating parameters such as catalyst dosage, light intensity, pH of the solution, the initial phenol, and H₂O₂ concentrations on photodegradation process were examined. It was shown that photodegradation using H₂O₂/TiO₂/UV process was much more effective than using either H₂O₂/UV or TiO₂/UV process. The effect of the initial phenol concentration on TOC removal was also studied, demonstrating that more than 8 h was required to completely mineralize phenol into water and carbon dioxide. For all the four oxidation processes studied, photodegradation followed the first-order kinetics. The apparent rate constants with 400-W UV ranged from 5.0 × 10⁻⁴ min⁻¹ by direct photolysis to 1.4 × 10⁻² min⁻¹ using H₂O₂/TiO₂/UV process. The role of H₂O₂ on such enhanced photodegradation of phenol in aqueous solution was finally discussed.     

双膜强化类Fenton工艺处理制浆废水的研究

类Fenton工艺又称非均相Fenton工艺,主要用于降解废水COD,可避免传统Fenton工艺产生的铁泥问题,但双氧水利用率尚有待提高。采用1个陶瓷膜分布H₂O₂,另1个陶瓷膜分离催化剂,构成双膜促进的非均相Fenton新工艺,考察了不同催化剂对制浆废水中COD的降解效果,优化了H₂O₂进料速率和反应渗透通量,分析了催化剂的稳定性和陶瓷膜污染情况。结果表明,自制立方体结构的Cu₂O对制浆废水中COD降解效果最佳,当Cu₂O添加量为1 g·L^-1,H₂O₂加入量为0.8 ml·L^-1,反应温度为30℃,反应渗透通量为137 L·m^-2·h^-1时,RO（Ⅰ）～RO（Ⅳ）4种废水的COD降解量分别为11、130、291和417 mg·L^-1,H₂O₂的利用率分别为9%、106%、232%、334%,H₂O₂利用率大于100%的主要原因是废水中大量的氯离子与铜催化剂作用产生氯自由基参与了降解反应,COD降解量与Cl-含量呈现线性关系,并且COD降解率随膜渗透通量的减小而增大。360 min的连续运行表明陶瓷膜分布器在非均相Fenton反应过程中会形成可逆滤饼层,膜污染较小,COD降解率稳定保持在65%以上。随着制浆废水中盐浓度的增大,Cu₂O催化剂稳定性变差,Cu离子的溶出量增大。陶瓷膜可以强化非均相Fenton工艺处理制浆废水效果,提高双氧水的利用率和连续运行的稳定性。     

Comparative evaluation of Fe and TiO2 photoassisted processes in solar photocatalytic disinfection of water

A lost of culturability of bacteria Escherichia coli K12 was observed after exposition to a solar simulator (UV–vis) in a laboratory batch photoreactor. The bacterial inactivation reactions have been carried out using titanium dioxide (TiO₂) P25 Degussa and FeCl₃ as catalysts. At the starting of the treatment, the suspensions were at their “natural” pH. An increase in the efficiency in the water disinfection was obtained when some advanced oxidation processes such as UV–vis/TiO₂, UV–vis/TiO₂/H₂O₂, UV–vis/Fe³⁺/H₂O₂, UV–vis/H₂O₂ were applied. The presence of H₂O₂ accelerates the rate of disinfection via TiO₂. The addition of Fe³⁺ (0.3 mg/l) to photocatalytic system decreases the time required for total disinfection (<1 CFU/ml), for TiO₂ concentrations ranging between 0.05 and 0.5 g/l. At TiO₂ concentrations higher than 0.5 g/l the addition of Fe³⁺ does not significantly increase the disinfection rate. The systems: Fenton (H₂O₂/Fe³⁺/dark), H₂O₂/dark, H₂O₂/TiO₂/dark showed low disinfection rate. The effective disinfection time (EDT₂₄) was reached after 60 and 30 min of illumination for the Fe³⁺ and TiO₂ photoassisted systems, respectively. EDT₂₄ was not reached for the system in the absence of catalyst (UV–vis). The effect on the bacterial inactivation of different mixture of chemical substance added to natural water was studied.     

金属氧化物掺杂高岭土纳米 二氧化钛光催化复合材料研究

以高岭石为载体,以钛酸四丁酯为前驱体,采用溶胶-凝胶法制备金属氧化物掺杂高岭土纳米二氧化钛光催化复合材料。采用X射线衍射（XRD）、红外光谱（FT-IR）和拉曼光谱（Raman）对复合材料进行表征,并通过在紫外光下降解云母珠光工业废水来考察其光催化性能。研究了不同金属氧化物掺杂浓度对复合材料光催化活性的影响。实验结果表明：金属氧化物三氧化二铁、氧化锌掺杂使锐钛矿二氧化钛晶相特征衍射峰宽化,掺杂生成钛铁矿、红锌矿新相,影响锐钛矿二氧化钛结晶度。在紫外光下降解6 h,掺杂质量分数为0.5%的三氧化二铁对废水降解率为98.8%,掺杂质量分数为1.5%的氧化锌对其降解率为91.4%。     

Decolorization of reactive brilliant red X-3B by heterogeneous photo-Fenton reaction using an Fe–Ce bimetal catalyst

Decolorization of reactive brilliant red X-3B was studied by using an Fe–Ce oxide hydrate as the heterogeneous catalyst in the presence of H₂O₂ and UV. The decolorization rate was in the order of UV–Fe–Ce–H₂O₂ > UV–Fe³⁺–H₂O₂ > UV–H₂O₂ > UV–Fe–Ce ≥ Fe–Ce–H₂O₂ > Fe–Ce. Under the conditions of 34 mg l⁻¹ H₂O₂, 0.500 g l⁻¹ Fe–Ce, 36 W UV and pH 3.0, 100 mg l⁻¹ X-3B could be decolorized at efficiency of more than 99% within 30 min. The maximum dissolved Fe during the reaction was 1 mg l⁻¹. From the fact that the decolorization rate of the UV–Fe–Ce–H₂O₂ system was significantly higher than that of the UV–Fe³⁺–H₂O₂ system at Fe³⁺ = 1 mg l⁻¹, it is clear that the Fe–Ce functioned mainly as an efficient heterogeneous catalyst. UV–vis, its second derivative spectra, and ion chromatography (IC) were employed to investigate the degradation pathway. Fast degradation after adsorption of X-3B is the dominant mechanism in the heterogeneous catalytic oxidation system. The first degradation step is the breaking down of azo and CN bonds, resulting in the formation of the aniline- and phenol-like compounds. Then, the breaking down of the triazine structure occurred together with the transformation of naphthalene rings to multi-substituted benzene, and the cutting off of sulphonic groups from the naphthalene rings. The last step includes further decomposition of the aniline structure and partial mineralization of X-3B.     

Degradation of neonicotinoid insecticides by different advanced oxidation processes and studying the effect of ozone on TiO2 photocatalysis

Although some studies concerning the effect of pH and ozone dosage on TiO₂ photocatalysis (O₂/TiO₂/UV) have already been published, no complete investigation and explanation of the effects of both parameters on photocatalytic ozonation (O₃/TiO₂/UV) have been carried out. Aqueous solutions of neonicotinoid insecticides (thiacloprid and imidacloprid) were chosen as a degradation medium, since they exhibit a high threat for aquatic systems and it is of great importance to find an effective method for their elimination from the environment. In preliminary stability tests, thiacloprid showed higher photo- and chemical stability compared to imidacloprid, therefore its degradation was studied in detail. To assess the suitability of various treatments for degradation and mineralization of thiacloprid in water at different pH values and ozone dosages, we applied ozonation (O₃) and three different photochemical advanced oxidation processes, namely ozonation, coupled with UV radiation (O₃/UV), O₃/TiO₂/UV and O₂/TiO₂/UV. Light source emitting mainly in UVA range was applied in all three processes. The photocatalytic ozonation (O₃/TiO₂/UV) was found to be the most efficient process irrespective of pH. The synergistic effect of ozone and TiO₂ photocatalysis was noticed at acidic and neutral pH, but the synergism was lost at basic pH, probably due to faster self-decompositon of ozone under alkaline conditions. At acidic pH, also the oxidation of chloride anions to chlorate(V) was noticed in O₃/TiO₂/UV and in O₃/UV processes. By plotting the disappearance rate constants of thiacloprid degradation in O₃/TiO₂/UV and O₃/UV systems as a function of the flow rate of ozone, the synergistic effect of ozone was undoubtedly proven. The slope of the linear fit in case of O₃/TiO₂/UV process was considerably steeper than in case of O₃/UV, which would not happen in absence of synergistic effect. The linearity in O₃/TiO₂/UV system was lost only at very high flow rates of ozone.     

Oxalic acid destruction at high concentrations by combined heterogeneous photocatalysis and photo-Fenton processes

Heterogeneous photocatalysis (HP) using UV/TiO₂, photo-Fenton (PF) reaction using UV/Fe/H₂O₂ and the combination UV/TiO₂/Fe/H₂O₂ (HP–PF) were tested as processes to degrade oxalic acid (Ox) at relatively high concentrations (0.032 M). PF reactions were generally more efficient than HP including the reaction in the absence of H₂O₂. Oppositely to previous results (e.g., with EDTA), HP–PF combinations did not result, in the case of oxalate, better techniques for degradation than systems in the absence of TiO₂. The kinetic behavior was not unique and two parameters were taken to evaluate the efficiency of each system: initial rates (R₀) and time to 95% of total mineralization (TOC₉₅). Addition of hydrogen peroxide improves the initial HP reaction rate and reduces TOC₉₅. Addition of Fe³⁺ also affects the reaction parameters but the effect of H₂O₂ seems to be higher, at least under the present conditions. When both H₂O₂ and iron were added simultaneously, the efficiency was higher. The optimal H₂O₂:Ox:Fe molar ratio was established and the results indicated that, at a fixed iron concentration, H₂O₂ increased R₀ until a limit beyond which it did not cause any effect. No intermediates were formed in the reaction, oxalate being degraded directly to CO₂. Analogies and differences with the EDTA system are presented.