Carbon and nitrogen Isotope fractionation of the photo-degradation of herbicides in aqueous solution by nitrates under ultraviolet radiation

Abstract Background: Phenylurea herbicides are one of the most important and widely used pesticides in the world. Due to its potential persistence and toxicity in the aquatic environment, it poses certain risks to the ecological environment and human health. Studying the photochemical degradation behavior of herbicides is important for understanding the degradation and transformation fate in the environment.Results: This study evaluated the effectiveness of direct and indirect photo-degradation of the herbicides isopropiron (IUP) and methylamine (MN), investigating the influence of operational variables (initial herbicide concentration and light sources) and initial of induced nitrate concentration on these processes in aqueous solution. We also introduced a new technology of compound-specific isotope analysis (CSIA) to provide deeper information of the photochemical degradation mechanism. Results showed that the light source and the initial concentration have an important effect on the degradation of herbicides IUP and MN. The photolysis rate under the Hg lamp is higher than photolysis rate under Xe lamps. It is found that photolysis kinetics of herbicides were consistent with the quasi-first order model, and the photolysis rate decreases with the increasing of the initial concentration. In indirect photodegradation, the degradation rate increases with increasing NO 3 − concentration at low concentrations of pesticides (8 mg/L); while the degradation rate decreases with increasing NO 3 − concentration at high concentrations of pesticides (30 mg/L ). According to the isotope fractionation, photolysis of IUP exhibits normal carbon isotope fractionation with the degradation rate increases, and the stable isotope enrichment factors under different photolysis pathways are different. In the indirect photo-degradation process, no significant fractionation of nitrogen isotopes occurred, and stable nitrogen isotopes fractionation could not be fitted well in either of the two photodegradation pathways.Conclusion: Therefore, the structure and chemical characteristics of the molecules of herbicides play a determinant role in their photodegradation. The CSIA is useful both for a mechanism-based evaluation of experimental results and as a valuable tool to explore transformation pathways for organic pollutants in different environmental systems.

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Photo-Degradation of Cypermethrin in Aqueous Solution Studied by HPLC-DAD

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.634-638.1044 ◽

2013 ◽

Vol 634-638 ◽

pp. 1044-1048

Author(s):

Yan Ru Liang ◽

Zhen Bin Gong ◽

Wen Quan Li

Keyword(s):

Aqueous Solution ◽

High Performance ◽

Degradation Products ◽

Degradation Process ◽

Mass Spectrometric ◽

Photochemical Degradation ◽

Pseudo First Order Reaction ◽

Photo Degradation ◽

Mass Spectrometric Detector ◽

Degradation Reaction

The photo-degradation process of cypermethrin in aqueous solution was studied using the laboratory-built photochemical degradation device and commercial high performance liquid chromatography (HPLC) with ultraviolet-visible absorbance detector and mass spectrometric detector. Spectrometric characteristics of cypermethrin and its main degradation products suggest that cypermethrin could be photo-degradated and converted into smaller molecular under ultraviolet irradiation. The photo-degradation reaction of cypermethrin in aqueous solution is approximately pseudo-first-order reaction. Light strength, pH and salinity have significant effects on the photo-degradaiton reaction of cypermethrin. Mass spectrometric results show that cypermethrin pesticide can be degraded into new and easily photochemical degrading products through the removal of chlorine.

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Heteropolyacid Photocatalytical Degradation of Atrazine in Aqueous Solution under UV-Irradiation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.1680 ◽

2013 ◽

Vol 652-654 ◽

pp. 1680-1683

Author(s):

Wei Yang Shen ◽

Fei Ye Liu ◽

Jian Qiu Chen ◽

Rui Xin Guo

Keyword(s):

Aqueous Solution ◽

Organic Compounds ◽

Uv Irradiation ◽

Degradation Rate ◽

Ph Value ◽

Degradation Products ◽

Affecting Factors ◽

Obvious Effect ◽

Initial Concentration ◽

Temperature Exposure

The photodegradation of atrazine induced by UV-irradiation in aqueous solution was investigated initially. The affecting factors on the photodetradation were studied and described in details such as atrazine initial concentration, temperature, pH value, exposure intensity, oxidant and co-existing substances. It was found that the atrazine initial concentration had no obvious effect on the photodegradation. With the pH value increasing, photodegradation rates decreased. However, we also observed a positive correlation between the degradation rate of atrazine and temperature, exposure intensity and oxidant while the coexisting organic compounds may decelerate photodegradation of the atrazine in water. In this paper, the degradation products had also been confirmed by using LC-MS.

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Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽

10.32964/tj17.03.167 ◽

2018 ◽

Vol 17 (03) ◽

pp. 167-178 ◽

Cited By ~ 2

Author(s):

Xin Tong ◽

Jiao Li ◽

Jun Ma ◽

Xiaoquan Chen ◽

Wenhao Shen

Keyword(s):

Degradation Rate ◽

Southern China ◽

Catalytic Degradation ◽

Pulp And Paper ◽

Gaseous Pollutants ◽

Pulp And Paper Mills ◽

Paper Mills ◽

Initial Concentration ◽

First Order ◽

First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

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Photo-degradation of monoazo dye blue 13 using advanced oxidation process

10.31221/osf.io/dq46r ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Aqueous Solution ◽

Advanced Oxidation Process ◽

Oxidation Process ◽

High Energy ◽

Uv Exposure ◽

H2o2 Concentration ◽

Oxidizing Agent ◽

Photo Degradation ◽

High Energy Radiation ◽

Uv Lamp

The high energy radiation overcome the bonding of solute in a solution and H2O2 acts as an oxidizing agent and generates a free radical in the solution which results in photo-degradation by converting the solute in to simple form and resultantly, colored substance under the effect of photo-degradation becomes colorless. The photo-degradation of monoazo dye Blue 13 in an aqueous solution was investigated using a laboratory scale UV lamp in the presence of H2O2 and for maximum degradation of dye, the independent parameter UV power, UV exposure time, pH and H2O2 concentration were optimized. It was found that neither UV in the presence of H2O2 is able to degrade Blue 13 under optimum condition. The results revealed that the use of both UV and H2O2 have pronounced effect on the discoloration of dyes which could be used for management of textile effluents contain waste dyes.

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Comparative Bio-sorption of Cadmium and Nickel Ions from Aqueous Solution onto Fibers of Date Palm using Fluidized Bed Column

Revista de Chimie ◽

10.37358/rc.19.5.7160 ◽

2019 ◽

Vol 70 (5) ◽

pp. 1507-1512

Author(s):

Baker M. Abod ◽

Ramy Mohamed Jebir Al-Alawy ◽

Firas Hashim Kamar ◽

Gheorghe Nechifor

Keyword(s):

Aqueous Solution ◽

Heavy Metal ◽

Metal Ions ◽

Fluidized Bed ◽

Removal Efficiency ◽

Heavy Metal Ions ◽

Date Palm ◽

Operating Conditions ◽

Initial Concentration ◽

Bed Height

The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the removal of Cd(II), and Ni(II) ions from aqueous solution by fluidized bed column. The effects of many operating conditions such as superficial velocity, static bed height, and initial concentration on the removal efficiency of metal ions were investigated. FTIR analyses clarified that hydroxyl, amine and carboxyl groups could be very effective for bio-sorption of these heavy metal ions. SEM images showed that dry fibers of date palm have a high porosity and that metal ions can be trapped and sorbed into pores. The results show that a bed height of 6 cm, velocity of 1.1Umf and initial concentration for each heavy metal ions of 50 mg/L are most feasible and give high removal efficiency. The fluidized bed reactor was modeled using ideal plug flow and this model was solved numerically by utilizing the MATLAB software for fitting the measured breakthrough results. The breakthrough curves for metal ions gave the order of bio-sorption capacity as follow: Cd(II)]Ni(II).

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Use of Nanopillars-TiO2 Thin Films in the Photocatalytic Degradation of Bromophenol Blue from Aqueous Solution

Science & Technology Journal ◽

10.22232/stj.2018.06.01.03 ◽

2018 ◽

Vol 6 (1) ◽

pp. 22-30

Author(s):

C. Lalhriatpuia ◽

◽

Thanhming liana ◽

K. Vanlaldinpuia

Keyword(s):

Thin Films ◽

Aqueous Solution ◽

Photocatalytic Activity ◽

Photocatalytic Degradation ◽

Batch Reactor ◽

Bromophenol Blue ◽

Tio2 Thin Films ◽

Initial Concentration ◽

Bet Specific Surface Area ◽

Interfering Ions

The photocatalytic activity of Nanopillars-TiO2 thin films was assessed in the degradation of Bromophenol blue (BPB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the XRD, SEM and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data showed anatase phase of TiO2 particles with average particle size of 25.4 and 21.9 nm, for S1 and S2 catalysts respectively. The SEM and AFM images indicated the catalyst composed with Nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The average height of the pillars was found to be 180 and 40 nm respectively for the S1 and S2 catalyst. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of BPB using the UV light was studied at wide range of physico-chemical parametric studies to determine the mechanism of degradation as well as the practical applicability of the technique. The batch reactor operations were conducted at varied pH (pH 4.0 to 10.0), BPB initial concentration (1.0 to 20.0 mg/L) and presence of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of BPB. The maximum percent removal of BPB was observed at pH 6.0 and a low initial concentration of the pollutant highly favours the photocatalytic degradation using thin films. The presence of several interfering ions suppressed the photocatalytic activity of thin films to some extent. The time dependence photocatalytic degradation of BPB was demonstrated with the pseudo-first-order rate kinetics. Study was further extended with total organic carbon measurement using the TOC (Total Organic Carbon) analysis. This demonstrated an apparent mineralization of BPB from aqueous solutions.

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Preliminary Study on the Use of Ozonation for the Degradation of Dithiocarbamate Residues in the Fruit Drying Process: Mancozeb Residue in Blackcurrant is the Example Used

Journal of Plant Protection Research ◽

10.2478/jppr-2013-0007 ◽

2013 ◽

Vol 53 (1) ◽

pp. 48-52 ◽

Cited By ~ 8

Author(s):

Piotr Antos ◽

Anna Kurdziel ◽

Stanisław Sadło ◽

Maciej Balawejder

Keyword(s):

Aqueous Solution ◽

Ozone Concentration ◽

Gaseous Phase ◽

Plant Material ◽

Water Solution ◽

Ozone Treatment ◽

Drying Process ◽

Initial Concentration ◽

Preliminary Study ◽

Treatment Procedures

Abstract In order to reduce the level of dithiocarbamate fungicide mancozeb residues in blackcurrants, two different ozone treatment procedures were evaluated. The first one entailed washing the plant material with an aqueous solution of ozone. This ozone enriched water solution allowed for a 59% reduction of mancozeb residues, compared with the initial concentration. The latter method was based on the utilization of ozone in a gaseous phase combined with a drying process. In that procedure, samples of blackcurrant fruit were exposed to a 19 ppm ozone concentration, and then the blackcurrants were dried. The utilization of ozone in a gaseous phase permitted a 38% reduction of mancozeb residues, in comparison with the initial concentration. As a result of the combination of both processes; ozonation and drying, a 58% reduction of mancozeb residues was achieved.

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Adsorption of Thorium from Aqueous Solution using Nanoporous Adsorbents: Effect of Contact Time, pH, Initial Concentration, and Temperature

Particulate Science And Technology ◽

10.1080/02726351.2013.763880 ◽

2013 ◽

Vol 31 (4) ◽

pp. 372-378 ◽

Cited By ~ 2

Author(s):

Ali Malekynejad ◽

Hamid Sepehrian ◽

Mahbobeh Manoochehri

Keyword(s):

Aqueous Solution ◽

Contact Time ◽

Initial Concentration

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Removal of Cr(VI) from Aqueous Solution by Acid Treated Fungal Biomass

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.131 ◽

2011 ◽

Vol 197-198 ◽

pp. 131-135

Author(s):

Li Fang Zhang ◽

Ying Ying Chen ◽

Wen Jie Zhang

Keyword(s):

Aqueous Solution ◽

Fungal Biomass ◽

Adsorption Model ◽

Solution Ph ◽

Initial Concentration ◽

Biosorption Capacity ◽

Penicillium Sp ◽

Chromium Vi ◽

Equilibrium Data ◽

Biosorption Equilibrium

Biosorption of chromium (VI) ions from aqueous solution with fungal biomass Penicillium sp. was investigated in the batch system. The influence of contact time, solution pH, biosorbent concentration, initial concentration of Cr (VI) ions and temperature on biosorption capacity of Cr (VI) ions was studied. The uptake of Cr (VI) was highly pH dependent and the optimum pH for biosorption of Cr (VI) ions was found to be 2.0. Biosorption capacity of Cr (VI) ions decreased with increased biosorbent concentration and increased with increase in initial concentration of Cr (VI) ions. The experiment results also showed that high temperatures increased the biosorption capacity of Cr (VI) by fungal biomass. It was found that the biosorption equilibrium data were fitted very well to the kangmuir as well as to the Freundlich adsorption model. The maximum sorptive capacities obtained from the Langmuir equation at temperature of 20, 30 and 40°C were 25.91, 32.68 and 35.97 mg/g for Cr (VI) ions, respectively. The results of this study indicated that the fungal biomass of Penicillium sp. is a promising biosorbent for removal of chromium (VI) ions from the water.

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