Degradation of high-concentration simulated organic wastewater by DBD plasma

In this study, a high-concentration simulated organic wastewater, made by dissolving methyl violet in water, was degraded using dielectric barrier discharge (DBD) plasma generated in air and O2 respectively. The decoloration rate and chemical oxygen demand (COD) of wastewater were evaluated during plasma treatments with the initial concentration of methyl violet of 300 mg L−1. Results showed that the highest decoloration rate of around 100% within 10 min and the highest COD decrease of 33% within 60 min could be achieved with the O2 plasma treatment at the discharge voltage of 10 kV, while air plasma treatment showed lower efficiency in decolorizing the methyl violet solution and lower COD decrease (24%) after 60 min treatment. UV-Vis spectroscopy and chemical analysis of generated by-products during the plasma-enabled degradation process revealed that the methyl violet molecules could be completely decomposed into some refractory organics in the solution. Based on the experimental results and literature review, a pathway of methyl violet degradation attributed to energetic electrons and highly reactive species generated by DBD was proposed.

An Efficient Method for Decoloration of Inulin from Jerusalem Artichoke by Macroporous Resin

The decoloration method for Inulin from Jerusalem artichoke with activated carbon andmacroporous resin was investigated in this manuscript. Six resins (D113, D301, 001×7, 201×7,DA201-C and activated carbon) with same diameter were studied through static experiments.Meanwhile, the decoloration duration and resin dosage were also determined. Macroporous resinadsorption method was better than the traditional activated carbon adsorption method. The resultsalso suggested that the polar and ionogenic properties significantly affected the decoloration rate. The001×7-201×7 type resin which are strongly polar resin offered the better decolorizing effect. Most ofpigment impurities were successfully removed from inulin solutions with 1:10 resin dosage and 40min decoloration process. Moreover, the decoloration rate and inulin loss rate were 82.29% and 12.67%respectively. This study would provide a potential approach for large-scale production of inulin forits wide applications in dietary supplements.

Effect of Electrodes Material on the Performance of Batch Reactor Using Plasma Enhanced Technique for Wastewater Treatment

The plasma degradation process of Eosin yellow aqueous solution utilizing AC corona discharge generated above liquid with a type of pin to plate by utilizing multiple needles electrodesis investigated the influence of electrodes material and effect of ferrous sulfate on decoloration and the kinetics of process are discussed. The AC corona discharge plasma was generated in the air gap between tip of needles and the water surface. The experimental results indicate that the decoloration rate increases with using stainless steel electrodes and with increasing the concentration of FeSO4. When dye concentration is 10 mg/L with pH of 3, the air gaps were 0.85 cm and the number of pins were 30, the decoloration rate went up to 97% in 60 min.

The Effect of KNO3 on Electrolysis-Assisted Flocculation of Azophloxine Using Polyaluminum Chloride

Electrolysis-assisted flocculation methods were used in decoloration of azophloxine. Electrolysis-assisted flocculation of azophloxine was conducted under the applied potential using titanium anode. The concentration of KNO3, flocculating time and applied potential were investigated. The application of applied potential has nearly no power to remove the dye from wastewater since the highest decoloration rate is only 2.5% after treatment at KNO3 concentration of 0.6 mol/L. The total flocculating decoloration efficiency decreases gradually after increasing the KNO3 concentration in the solution. When the applied potential is 7 V, the maximum electrolysis-assisted flocculating decoloration rate is 52.3%. When the electrolysis-assisted flocculating time is 5 min, the maximum decoloration rate is 54.2%.

Electrolysis and Flocculating of Azophloxine Using Polyaluminum Chloride

Electrolysis and flocculation methods were used in decoloration of azophloxine. Electrolysis of azophloxine was conducted under the applied potential using titanium anode. Flocculation of azophloxine was conducted with the help of polyaluminum chloride as flocculating reagent. The solely application of applied potential has nearly no power to remove the dye from wastewater. The efficiency of azophloxine flocculation increases apparently when the amount of PAC is low in the solution. Decoloration rate reaches the maximum value of 57.5% after 15 mg PAC is added into the solution and is stirred for 10 min. The total decoloration efficiency decreases gently after increasing the initial azophloxine concentration in the solution.

Study on Ultrasonic Degradation of Methyl Orange Wastewater by Modified Steel Slag

In this paper, steel slag as the main raw material, modified steel slag adsorbent was prepared using steel slag and the active carbon as the starting materials. The influences of doping substance, the particle size, calcining temperature and doping ratio on the decoloration rate of methyl orange wastewater were investigated. The results showed that the decoloration rate of methyl orange can reach 93.62% when the doping substance was the activated carbon, the particle size was 120 mesh, the calcining temperature was 700°C, the doping ratio was 1:1.

Study on the Collaborative Degradation of Acid Red B Dye Wastewater by O3/H2O2

Acid Red B dye wastewater was collaborative degradated by ozone and hydrogen peroxide. Various reaction conditions are studied which affect on decoloration rates of wastewater. The decoloration rate of Wastewater increases with O3 gas flow rate increasing, and also increases with pH value increasing. O3/H2O2 collaborative effects are better than O3 alone, and the decoloration rate is higher with more H2O2 addition. Ozone Oxidation have a good effect to degrade Acid Red B dye wastewater, the decoloration rate can reach 98% with inflating O3 30min. H2O2 synergy can greatly increase the reaction rate, shorten the reaction time, improve the utilization of ozone.

Layer-by-Layer Assembly and Photocatalytic Activity of Titania Nanosheets on Coal Fly Ash Microspheres

In order to address the problem with titania distribution and recovery, series of Ti0.91O2/CFA photocatalysts (Ti0.91O2/CFA-n,n=2,4,6,and8) were fabricated by assembling Ti0.91O2nanosheets on coal fly ash (CFA) microspheres via the layer-by-layer assembly (LBLA) process and characterized by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), N2-sorption, and ultraviolet-visible absorption (UV-vis) techniques. The SEM images and UV-vis spectra illustrated that Ti0.91O2nanosheets were immobilized successfully on the CFA by the LBLA approach and changed the characteristics of CFA noticeably. The photocatalytic activity of Ti0.91O2/CFA was evaluated by the photodegradation of methylene blue (MB) under UV irradiation. The results demonstrated that Ti0.91O2/CFA-6 showed the best photocatalytic activity among the series of Ti0.91O2/CFA irradiated for 60 min, with a decoloration rate above 43%. After photocatalysis, the Ti0.91O2/CFA could be easily separated and recycled from aqueous solution and Ti0.91O2nanosheets were still anchored on the CFA.

Degradation of Crystal Violet by Pulsed Corona and Spark Discharge: Determination of Removal Mechanism

The pulsed discharge includes corona discharge and spark discharge. The voltage waveforms, photo, the decoloration rate of Crystal violet in corona discharge and spark discharge were investigated respectively. The results show that the spark discharge is more intense than the corona discharge. The decoloration rate of Crystal violet by spark discharge is 90%, which is higher than that corona discharge. From the UV-Visible and FTIR spectra, we can see that the molecular conjugated system and the benzene ring of CV were damaged by pulsed discharge.