Biomaterial Database

Degradation of six typical pesticides in water by VUV/UV/chlorine process: Evaluation of the synergistic effect. 2019

Laxiang Yang, and Zhenhua Zhang

College of Food and Chemical Engineering, Shaoyang University, No. 28, Lane 3, Shaoshui West Road, Shaoyang, 422000, Hunan, China. Electronic address: y366001031@126.com.

Vacuum ultraviolet/ultraviolet/chlorine (VUV/UV/chlorine) is considered a novel advanced oxidation process (AOP), but little is known about its kinetics for pollutant degradation in water treatment. This study investigated the degradation of six typical pesticides, namely dimethoate (DMT), atrazine (ATZ), prometon (PMT), propoxur (PPX), bromacil (BRM) and propachlor (PPC), by VUV/UV/chlorine. The results show that all pesticides were rapidly degraded by VUV/UV/chlorine with a high removal efficiency of over 95% after 60 s. The pesticide degradation fitted well with pseudo-first-order reaction kinetics and a significant synergistic effect was observed during the VUV/UV/chlorine process. The synergistic factor (FV/U/Cl) for DMT, ATZ, PMT, PPX, BRM and PPC were determined to be 1.75, 1.70, 2.06, 1.57, 2.84 and 1.61, respectively, indicating a synergistic improvement of 57%-184% for all pesticides. As hydroxyl radical (HO•) transformed into reactive chlorine species (RCSs), the contribution ratio of RCSs for the pesticide degradation was much higher than that of HO• in the VUV/UV/chlorine process, thus causing the synergistic effect. Solution pH ranging from 5.0 to 10.0 had various influence on the pesticide degradation by VUV/UV/chlorine. As initial concentration of free chlorine increased from 0 to 0.25 mM, the apparent rate constants of the pesticides kept on increasing while the FV/U/Cl first increased and reached the highest value, and decreased afterwards. The formation of nitrite was significantly inhibited during the degradation of all pesticides by VUV/UV/chlorine. It suggests that VUV/UV/chlorine is a promising AOP for the pesticide degradation in water treatment.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D010575	Pesticides	Chemicals used to destroy pests of any sort. The concept includes fungicides (FUNGICIDES, INDUSTRIAL); INSECTICIDES; RODENTICIDES; etc.	Pesticide
D002713	Chlorine	An element with atomic symbol Cl, atomic number 17, and atomic weight 35, and member of the halogen family.	Chlorine Gas,Chlorine-35,Cl2 Gas,Chlorine 35,Gas, Chlorine,Gas, Cl2
D014466	Ultraviolet Rays	That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.	Actinic Rays,Black Light, Ultraviolet,UV Light,UV Radiation,Ultra-Violet Rays,Ultraviolet Light,Ultraviolet Radiation,Actinic Ray,Light, UV,Light, Ultraviolet,Radiation, UV,Radiation, Ultraviolet,Ray, Actinic,Ray, Ultra-Violet,Ray, Ultraviolet,Ultra Violet Rays,Ultra-Violet Ray,Ultraviolet Black Light,Ultraviolet Black Lights,Ultraviolet Radiations,Ultraviolet Ray
D014618	Vacuum	A space in which the pressure is far below atmospheric pressure so that the remaining gases do not affect processes being carried on in the space.	Vacuums
D014867	Water	A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Hydrogen Oxide
D014874	Water Pollutants, Chemical	Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.	Chemical Water Pollutants,Landfill Leachate,Leachate, Landfill,Pollutants, Chemical Water
D018508	Water Purification	Any of several processes in which undesirable impurities in water are removed or neutralized; for example, chlorination, filtration, primary treatment, ion exchange, and distillation. It includes treatment of WASTEWATER to provide potable and hygienic water in a controlled or closed environment as well as provision of public drinking water supplies.	Waste Water Purification,Waste Water Treatment,Wastewater Purification,Wastewater Treatment,Water Treatment,Purification, Waste Water,Purification, Wastewater,Purification, Water,Treatment, Waste Water,Treatment, Wastewater,Treatment, Water,Waste Water Purifications,Waste Water Treatments,Water Purification, Waste