Electrooxidative Degradation of an Anthraquinone Dye with in-situ Electrogenerated Active Chlorine in a Divided Flow Cell

The purpose of this paper was to investigate the possibility of treating C. I. Reactive Blue 19 wastewater by electrochemical oxidation via electrogenerated active chlorine, using metallic oxide coatings （dimensional stable anode, DSA） as anode. The electrolysis for the simulated wastewater was conducted at a constant current. Absorbances at 592 nm and 255 nm were measured to follow the decolorization of the dye and the degradatin of its aromatic ring. After 4 h of electrolysis under the experimental conditions： current density of 15 A·m^-2, 0.2 mol·L^-1 NaCl, 0.1 mol·L^-1 Na2SO4, 0.1 mmol·L^-1 dye, initial pH=6.4 and T=30℃, 100% decolorization of the dye and about 45% degradation of its aromatic ring were achieved, while no obvious change of total organic carbon was observed. The experimental results suggest that the decolorization of the dye and degradation of its aromatic ring were directly affected by current density, temperature, concentrations of the dye and sodium chloride, while slightly affected by initial pH and sodium sulfate concentration; the decolorization of the dye and degradation of its aromatic ring followed pseudo-first-order kinetics; and indirect electrooxidation, using electrogenerated active chlorine, predominated in the electrochemical oxidation.

Unveiling the geometric site dependent activity of spinel Co_(3)O_(4)for electrocatalytic chlorine evolution reaction

Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.

Self-powered electrochemical system by combining Fenton reaction and active chlorine geheration for organic contaminant treatment

Environmental deterioration,especially water pollution,is widely dispersed and could affect the quality of people's life at large.Though the sewage treatment plants are constructed to meet the demands of cities,distributed treatment units are still in request for the supplementary of centralized purification beyond the range of plants.Electrochemical degradation can reduce organic pollution to some degree,but it has to be powered.Triboelectric nanogenerator(TENG)is a newly-invented technology for low-frequency mechanical energy harvesting.Here,by integrating a rotary TENG(R-TENG)as electric power source with an electrochemical cell containing a modified graphite felt cathode for hydrogen peroxide(H2O2)along with hydroxyl radical(·OH)generation by Fenton reaction and a platinum sheet anode for active chlorine generation,a self-powered electrochemical system(SPECS)was constructed.Under the driven of mechanical energy or wind flow,such SPECS can efficiently degrade dyes after power management in neutral condition without any O2 aeration.This work not only provides a guideline for optimizing self-powered electrochemical reaction,but also displays a strategy based on the conversion from distributed mechanical energy to chemical energy for environmental remediation.

Evaluation of CC2 as a Decontaminant in Various Hydrophilicand Lipophilic Formulations Against Sulphur Mustard

Objective To evaluate CC2 (N, N’-dichloro-bis [2, 4, 6-trichlorophenyl] urea) invarious hydrophilic and lipophilic formulations as a personnel decontaminant for sulphurmustard (SM). Methods Twenty percent of CC2 was prepared as a suspension or ointmentwith various chemical agents and its stability was evaluated by active chlorine assay. Theefficacy was evaluated in mice by recording the mortality after applying 29 LD50 of SM (LD50 =8.1 mg/kg dermally) and decontaminating it after 2 min with 200 mg of the formulation.Studies were also carried out with 10% and 20% CC2 in acacia and hydroxypropyl cellulose,and the suspensions were stored in polyethylene containers. The stability of the suspensionswas evaluated by active chlorine assay. The efficacy was evaluated by recording themortality after applying 29 LD50 of SM in mice and 12 LD50 of SM in rats (LD50 = 2.4 mg/kgdermally), and decontaminating it with the formulations. LD50 by different routes andprimary skin irritation test of CC2 were also carried out. Results CC2 reacted with peanutoil and neem oil, and was unstable in povidone iodine and Fuller’s earth. Good stability wasachieved with petroleum jelly, honey, polyvinyl pyrrolidone, calamine lotion, acacia andhydroxypropyl cellulose. Though CC2 was stable in lipophilic formulations, it did notprotect the animals. The hydrophilic formulations particularly acacia and hydroxypropylcellulose gave very good protection and was stable in the polyethylene containers for aperiod of 1 year. The efficacy of 20% CC2 was better than 10% CC2. The oral and dermalLD50 of CC2 was found to be above 5.0 g/kg. CC2 was also found to be nonirritant.Conclusion Twenty percent of CC2 in hydroxypropyl cellulose is better with respect tostability, efficacy and ease of decontamination. CC2 is also a safe chemical.

Characterization of NOM and THM formation potential in eutrophic reservoir water

Resin adsorption technique with XAD-8 and XAD-4 was used to characterize the raw water from Erlong reservoir in Jilin province of China. The NOM chemical composition sequences of four organic fractions in the raw water, from high to low, are fulvic acid （FA） fraction, hydrophilic non-acid （HPINA） fraction, hydrophilic acid （HPIA） fraction, and humic acid （HA） fraction. Experimental results show that FA is the main precursor of THMFP among the four organic fractions. However, HA or hydrophobie acid exhibits the highest chlorination activity in forming THMs. It is also found that the value of FI/DOC or SUVA and the specific THMFP have better positive correlation. It is implied that certain source water has unique nature of NOM and DBPs.

CI Depletion in the 2006 Antarctic Stratosphere

An examination of the seasonal and spatial distribution of PSCs （polar stratospheric clouds） inferred from standard temperature profiles in the lower-middle atmosphere above Antarctica, as derived from the EOS （earth observing system） Aura MLS （microwave limb sounder） satellite observations and NCEP/NCAR （National Centers for Environmental Prediction/National Center for Atmospheric Research） assimilations, is provided. Chemical VMR （volume mixing ratio） observations of EOS Aura MLS v2.2 HCI （hydrogen chloride） were used to show the interannual variability of PSC formation with respect to stratospheric chlorine partitioning in 2006. A remarkable first set of results, obtained from an algorithm developed for modelling HCI depletion areas in the Antarctic polar vortex region, and based on satellite observations, is presented. In particular, the analysis of HCI concentration data obtained from 2006 indicated that the area processed for HCI was larger than the area of PSC during some periods of Antarctic winter, and that this result was robust with respect to the various PSC formation and HC1 depletion thresholds utilized. The results suggest that an underestimation in chlorine activation area can occur when temperature thresholds for PSC formation thresholds are employed.