在线分光光度法对Fenton降解活性蓝的降解动力学研究

利用在线分光光度法对活性蓝模拟废水的Fenton降解过程进行研究,探讨了过氧化氢浓度、二价铁离子浓度、温度、pH值和活性蓝浓度等因素对活性蓝降解的影响规律.结果表明Fenton降解过程分为两个拟一级动力学过程,反应初期降解速率常数(k1)和反应后期降解速率常数(k2)差约一个数量级.k1与Fe2+初始浓度线性正相关;H_2O_2初始浓度和pH值存在最佳值,分别为3.519 mmol/L和3;提高体系温度能够加快反应达到平衡的时间,反应活化能为25.21 k J/mol.

Apparent 1^st order rate constant of photodegradation of formaldehyde by carbon containing TiO2 nanoparticles

The apparent 1^st order rate constant of photodegradation of formaldehyde by carbon containing TiO2 nanoparticles has been investigated by numerical integration of mass transfer equation with measured degradation degree using a tubular photoreactor. The carbon containing TiO2 nanoparticles are synthesized by the oxidation of TiCl4 in propane/air flame CVD process with futile fraction up to 0.3 and carbon mass fractions up to 0.22, respectively. Thin TiO2 film is coated on the wall of the tubular reactor by sedimentation method. Effects of rutile mass fraction and carbon content have been examined on the apparent 1 ^st order rate constant and results show that, at 570ppm of formaldehyde loaded air stream, 80% relative humidity and about 100nm thin TiOa film, the 1^st order rate constant increases with increasing rutile mass fraction up to 0.3, occurs a maximum at the carbon content of about 5% by weight and is about 2.5 times of that at carbon content about zero or above 10%.

Portable wastewater treatment system based on synergistic photocatalytic and persulphate degradation under visible light

Highly efficient,low-cost,and portable wastewater treatment and purification solutions are urgently needed for aqueous pollution removal,especially at remote sites.Synergistic photocatalytic (PC) and persulphate (PS) degradation under visible light offers an exceptional alternative for this purpose.In this work,we coupled a TiO^(2-)based PC system with a PS oxidation system into a portable advanced oxidation device for rapid and deep degradation of organic contaminants in wastewater.Using hydrogenation,we fabricated hydrogenated anatase branched-rutile TiO_(2) nanorod (H-AB@RTNR) photocatalysts which enable the PC degradation to occur under visible light and improve the utilization of solar energy.We also discovered that the addition of PS resulted in the synergistic degradation of tenacious and persistent organics,dramatically improving the extent and kinetics of the degradation.A degradation rate of 100%and a reaction rate constant of 0.0221 min^(-1)for degrading 1 L rhodamine B(20 mg L^(-1)) were achieved in 120 min in a specially designed thin-layer cell under visible light irradiation.The superior performance of the synergistic PC and PS degradation system was also demonstrated in the degradation of real industrial wastewater.Both remarkable performances can be attributed to the heterophase junction and oxygen vacancies in the photocatalyst that facilitate the catalytic conversion of PS anions into highly active radicals (·SO_(4)-and·OH).This work suggests that the as-proposed synergistic degradation design is a promising solution for building a portable wastewater treatment system.