Papers by Keyword: Decolorization

Abstract: This study explored the decolorization kinetics of azo dye (methyl orange) with the presence of high entropy alloys (HEAs) as a catalyst in the Fenton process. The kinetic reaction of the azo dye was determined using the first and second-order kinetics model. The slope from the first pseudo kinetics model was determined to compute the decolorization rate constant (K) This present work showed that the model was significantly well fitted with the experimental data. The highest K value of HEA catalyst was occurred at 30 minutes within 60 minutes of the Fenton reaction. The obtained result also showed the efficiency of the high entropy alloys (HEAs) rapidly degraded the azo dyes.

Abstract: The tableware soda-lime silicate glasses, contained with 0.06 wt% of iron oxide, which were annealed at different times and temperatures, were investigated by UV-Vis spectroscopy. The glasses were produced from high iron sand. The iron content was twice as high in the glasses as it is in normal tableware glasses. The redox reaction of iron around glass transition temperature, Fe²⁺(green) ↔ Fe³⁺(yellow), was found in the annealing process, according to the redox reaction of iron with polyvalent ions in the glass, nFe³⁺ + M^a+ ↔ nFe²⁺ + M^(a+-n) where M is the polyvalent ion in glass. In this study, the glasses were prepared by melting in a platinum crucible. After casting, they were annealed with variable times and temperatures. The results of color in CIE L*a*b* system and Fe²⁺/Fe³⁺ ratio of glasses showed the effect of the annealing process on the redox reaction of iron. The decolorizing was found during the annealing process. The results of this work led to the method for controlling the effect of iron oxide in the glass and the possibility to use high iron sand to produce tableware glasses.Tableware glass, Iron oxide, Redox reaction, Decolorizing

Abstract: Textile and dyes industries are generating huge amount of waste water contains significant amount of dyes which are toxic and hazardous for the environment. Recently, advanced oxidation processes (AOPs) have considerable attention because it offers an attractive method for degradation of organic compounds and color from wastewater. The present work is focused on the heterogeneous photocatalytic degradation of Alizarin Cyanine Green and Acid Orange 7 dye using UV/TiO₂ process. The degradation of dyes is strongly dependent on the various operational parameters like initial concentration of dye, pH and loading of TiO₂. The kinetics of degradation of dye in the solutions was found to pseudo first order kinetics. A statistical technique response surface methodology was employed to study the influence of various operational parameters on degradation efficiency. Three-factor-three-level Face Centered Design was used for design of experiments. For 100 mg/L concentration of Alizarin Cyanine Green and Acid Orange 7 dyes, the optimum parameters were found to be 1.2 gm/L and 1.4 gm/L TiO₂ loading for maximum degradation of 97% and 65% respectively.

Abstract: Water pollution due to the discharges of textile wastewater without treatment is the most concern problem identified. This reduces the degree penetration of sunlight into the water. It causes some human health problem such as bladder cancer, liver cancer and splenic tumor. The biological research using Lactobacillus bacteria was developed to reduce the environment problems. This research was studied on the impact of Lactobacillus delbrueckii on decolorization of textile wastewater enhanced by Gigantochloa ligulata nutrient. This nutrient contains high protein, mineral, moisture and carbohydrate such as fructose, glucose and sucrose. Those nutrients are used by Lactobacillus species to produce lactic acid, which simultaneously help in decolorizing textile wastewater. The effect studies; Lactobacillus delbrueckii dosage (4, 7, 10 mL/mL), agitation speed (1, 75.5, 150 rpm) and dye concentration (0.1, 0.55, 1.0 mL/mL) were performed to determine the rate of decolorization for every 24 hours. The result obtained show the maximum decolorization rate, 65.30% occurs at 7.66 mL of Lactobacillus dosage and 0.49 mL/mL of dye concentration with 64.20 rpm. It can be concluded that Gigantochloa ligulata nutrient has potential in enhancing Lactobacillus species to decolorize of textile wastewater.

Abstract: Decolorization of azo dye, reactive black 5 (RB5) in an aqueous solution was investigated by using Fe-areca nut (Fe-AN) as heterogeneous catalyst. The effect of different parameters such as iron ions loading on supported catalyst, catalyst dosage, solution pH and initial concentration of H₂O₂ on the decolorization efficiency of the process were studied. The Fe-AN was prepared by impregnation process where iron ions were immobilized into areca nut and followed by calcinations process. The best reacting conditions were 4 wt% of iron ions loading on areca nut, catalyst dosage=1.0 g/L, initial pH= 2.5, [H₂O₂] o = 16 mM at temperature 30°C. Under these conditions, 99% decolorization efficiency of RB5 was achieved within 180 min reaction time. The results indicated that Fe-areca nut has proven to be an excellent heterogeneous catalyst for the decolorization of RB5 solution.

Abstract: Studies were carried out on the decolorization of Direct Red 28 (DR) and Direct Yellow 12 (DY) by developed bacterial consortium. Effects of pH, temperature, and NaCl concentrations on degradation were studied. GC-MS was used to detect the intermediates produced in the effluents of anaerobic step. The optimum pH and temperature for the degradation of DR and DY were pH 7 and 6, and 37°Cand 45°C, respectively. We observed the peak of benzenamine in GC-MS analysis. The products formed during the reduction of DY12 were benzenamine and 2-Amino-1-hydroxybenzene. The results showed a complete degradation of DY12 by the bacterial consortium.

Abstract: To select a suitable decolorizing resin for Limonium bicolor Kunze (Bge.). polysaccharides (LBPs), the decolorization effect of crude LBPs by five resins are studied. And the adsorption equilibrium of LBPs pigment on the selected resin was investigated.The results show that the decolorization ratios of LX-46 is higher than those of other resins. Under optimized dynamicad sorption conditions (flow rate of 1.5BV/h, 2BV of 6mg/ml LBPS solution in 298K), the decoloration, deproteinization and polysaccharide recovery ratios of LX-46 resin were 92.08%, 92.79% and 86.53%, respectively. The above results show that macroporous anion exchange resins are suitable for the decolorization of crude LBPs.

Abstract: An effective method for decolorization of the polysaccharides from Lethariella spp. was studied. Decolorization rate was used as an indicator in the experiment, single factor text and orthogonal experiment was used to get the optimal conditions, the single factor experiment was carried out with temperature at 35°C, 45°C, 55°C, 65°C, and 75°C, the activated carbon added at 0.5%, 1%, 1.5%, 2%, and 2.5%, and time at 10, 15, 20, 25, and 30min, respectively. The optimal conditions of Lethariella spp. clarification using activated carbon were carried out to get the optimal conditions (the temperature at 55°C, the activated carbon added at 1%, and time was 25 min, and the decolorization rate could reach 57.56 %).

Abstract: Salt lakes with large reserves of mineral resources are widely distributed in China. In addition to aboundant inorganic substances, there also exist a mass of organic compounds in the brine. It is realized these organic compounds can produce serious negative effects on the process equipment and products quality. In this work, the decolorization and COD removal of the brine by ozonation were investigated in a bubble column reactor. The effects of contact time, ozone-air flow rate, pH and temperature on the decolorization and COD removal were investigated. It was found that the decolorization and COD removal rates increased with increasing ozone-air flow rate and contact time, while increased first and then decreased with increasing temperature and pH. Under the optimal conditions, color removal reached 47.3% and COD was reduced by 42.2%. Thus, ozonation can be used as the pretreatment method for decolorization and COD removal of the brine.

Abstract: The decolorization of methyl orange wastewater by DC stream discharge with MgO-CuO-Al₂O₃ catalyst was investigated. The removal efficiency was studied for different experimental parameters. Results showed that the removal efficiency by discharge with catalyst was better than discharge only. The removal efficiency was 98% under the condition of applied voltage 18kV, current 9mA, volume of catalyst 20cm³, initial concentration 40mg/L with treatment for 10min. The intensity of methyl orange absorption peak (465nm) gradually weakened and disappeared by discharge with catalyst, the conjugated system composed of azo group and benzene in the molecular structure was destroyed, methyl orange molecules were degraded effectively.