Effect of two types of reflective surfaces with different geometry in a solar pilot plant for the photocatalytic degradation of RB5 dye using a TiO 2 /rGO nanocomposite

Bisphenol A (BPA) and reactive black 5 (RB5) dye are among the most persistent and non-biodegradable contaminants in water which require an urgent need for the development of effective removal method. The ubiquitous existence of both contaminants could interfere with the human health and aquatic environmental balance. Photocatalytic process as one of advanced oxidation processes (AOPs) has shown high performance for degradation of organic compounds to the harmless materials under sensible condition. Therefore, this study aims to develop a visible-light-driven photocatalyst that can efficiently degrade BPA and RB5 present in household water. N-doped TiO2 were successfully synthesized via simple and direct sol–gel method. The prepared TiO2 nanoparticles were characterized by field emission scanning microscope (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Brunauere Emmette Teller (BET) analysis. The incorporation of nitrogen in TiO2 lattice exhibited excellent optical responses to visible region as revealed by UV–Vis–NIR spectroscopy absorption capability at 400–600 nm. The photocatalytic activity of the N-doped TiO2 nanoparticles was measured by photocatalytic degradation of BPA and RB5 in an aqueous solution under visible-light irradiations. Degradation of BPA and RB5 was 91.3% and 89.1%, respectively after 360 min illumination. The degradation of BPA and RB5 by N-doped TiO2 was increased up to 89.8% and 88.4%, respectively under visible-light irradiation as compared to commercial TiO2 P25. This finding clearly shows that N-doped TiO2 exhibits excellent photocatalytic degradation of BPA and RB5 under visible irradiation, hence have a promising potential in removing various recalcitrant contaminants for water treatment to fulfill the public need to consume clean water.

Heterogeneous activation of peroxymonosulfate with Fe3O4 magnetic nanoparticles for degradation of Reactive Black 5: Batch and column study

Degradation of Reactive Black 5 by electrochemical oxidation

Reactive black 5 dyeing wastewater treatment by electrolysis-Ce (IV) electrochemical oxidation technology: Influencing factors, synergy and enhancement mechanisms

Herein, two sunlight responsive photocatalysts including TiO2 nanoparticles (NPs) and TiO2/graphene quantum dots (GQDs) nanocomposite for degrading a textile dye, Reactive Black 5 (RB5), were prepared. The results showed that 100% of 50ppm RB5 could be degraded by TiO2 NPs and TiO2/GQDs within 60 and 30min sunlight irradiation, respectively. Hence, much better photocatalytic activity in degradation of RB5 was achieved by TiO2/GQDs under sunlight irradiation compared with pure TiO2 NPs due to its lower band gap (2.13eV) and electron/hole recombination rate. The photocatalytic degradation mechanism of RB5 by TiO2 NPs was elucidated by adding some scavengers to the solution. The main reactive species contributing to RB5 degradation were surface hydroxyl radicals. The first-order solar degradation rate constant of RB5 for TiO2/GQDs is greater than that of TiO2 NPs under sunlight illumination.

The present study is based on a hybrid advanced oxidation process (AOP) of sono-photolysis system, of which sonication (35 kHz) and photolysis UV-C (254nm) were applied simultaneously to effectively degrade a selected recalcitrant dye-based pollutant, Reactive Black 5 (RB5). The influence of the solution pH and concentration were manipulated throughout this study to investigate the sonophotodegradation kinetics and synergistic effects on the RB5 degradation. Increasing the solution concentration resulted in lowered degradation rate due to the inner filter effect by the dye molecules and reduced the generation of hydroxyl radicals. The results confirmed that the sonophotolysis rate was better at basic medium (67.7%) in comparison to acidic medium (46.9%) due to the ionization of RB5. Synergistic effects were analyzed based on the first order kinetic rate model. It was found that the synergistic effect was observed for all the experiments conducted which resulted from an increase in the (•OH) radicals due to the photolysis of H2O2 formed by the sonolysis process. This hybrid system, sonophotolysis system, was able to degrade RB5 into intermediates with a total reaction time of 1h.

This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in degradation of Reactive Black 5 (RB5) and generation of electricity. Zinc oxide (ZnO) was immobilized onto carbon felt acted as photoanode, while Pt-coated carbon paper as photocathode was placed in a single chamber photocatalytic fuel cell, which then irradiated by UV lamp for 24h. The degradation and mineralization of RB5 with 0.1M NaCl rapidly decreased after 24-h irradiation time, followed by MgSO4, Na2SO4 and without electrolyte. The voltage outputs for Na2SO4, MgSO4 and NaCl were 908, 628 and 523mV, respectively, after 24-h irradiation time; meanwhile, their short-circuit current density, J SC, was 1.3, 1.2 and 1.05mAcm(-2), respectively. The power densities for Na2SO4, MgSO4 and NaCl were 0.335, 0.256 and 0.245mWcm(-2), respectively. On the other hand, for without supporting electrolyte, the voltage output and short-circuit current density was 271.6mV and 0.055mAcm(-2), respectively. The supporting electrolyte NaCl showed greater performance in degradation of RB5 and generation of electricity due to the formation of superoxide radical anions which enhance the degradation of dye. The mineralization of RB5 with different supporting electrolyte was measured through spectrum analysis and reduction in COD concentration.

Efficient and cost-effective method to destroy complex dyes is warranted to combat increasing water pollution. In the present study, homogeneous photocatalytic oxidation (PCO) of Reactive Black 5 (RB5) dye was studied using ferric ions (Fe(III)) under visible light (VL) irradiation and sunlight (SL). In the presence of 5 mM ferric ions and at pH 2.6, more than 80% of initial 20 mg/L RB5 was decolourized in 60 min under artificial VL. Decolourization followed pseudo first-order kinetics with the reaction rate constant 0.0356 min−1. 79% of initial COD was removed at the end of 60 min, suggesting mineralization of RB5 as the main cause of decolourization. Using similar experimental conditions under SL, more than 90% RB5 was decolourized in 15 min with an almost 10-fold increase in the reaction rate constant (0.34 min−1). Rate and extent of RB5 destruction significantly decreased in the presence of •OH scavenger indicating photoreduction of Fe-hydroxo species and generation of •OH as the main mechanism of RB5 degradation. RB5 removal increased from ca. 30% to 84% with the increase in Fe(III) concentration from 0.5 to 5 mM. The corresponding 1st-order rate constants increased linearly from 0.006 to 0.036 min−1. RB5 degradation decreased linearly (R2 = 0.98) from 91.7% to 63.3% with the increase in initial RB5 concentration from 10 to 40 mg/L. Fe(III) induced homogenous PCO appears to be a reliable and low-cost method of advanced oxidation without the need for costly reagent such as H2O2.

Copper ferrite nanoparticles loaded on montmorillonite (MMT−CuFe 2 O 4 ) were prepared by co‐precipitation method and applied as catalyst for activation of peroxymonosulfate (PMS) in degradation of reactive black 5 (RB5). The maximum removal efficiency of RB5 completely depends on the operating parameters and the highest removal percentage was obtained at MMT−CuFe 2 O 4 dosage of 250 mg/L, PMS concentration of 4 mM, initial RB5 concentration of 50 mg/L and time of 15 min. The presence of anions such as Cl − , NO 3 − , HCO 3 − , and SO 4 2− showed a significant limitation in the degradation of RB5 in the MMT−CuFe 2 O 4 /PMS system. Trapping experiments showed that ⋅OH and SO 4 ⋅ − radicals were involved in the catalytic degradation of RB5, however ⋅OH is the major specie in the catalysis system. Consecutive cycles were considered for testing the reusability of MMT−CuFe 2 O 4 ; its results showed the stability of five consecutive cycles. The toxicity test was evaluated using Daphnia magna and the results illustrated a substantial drop in the toxicity of the solution treated. The significant reduction of TOC during RB5 degradation and the production of SO 4 2− , NH 4 + and NO 3 − confirm the proper progress of pollutant mineralization. The high catalytic performance of the catalyst in a short time compared to other removal systems emphasizes that MMT−CuFe 2 O 4 can be suggested as a promising catalyst for the degradation of RB5 from aqueous solutions.

A study has been performed on the degradation of Reactive Black 5 (RB5) as pollutant using iron electrode (Fe.S) derived from iron sludge steel waste via electrochemical method. The Fe.S and titanium graphite electrodes were applied as anode and cathode respectively during the studied. The studied operating parameters were the effect of current density, initial pH, initial concentration, and the reusability of the Fe.S electrode. The experiment was carried out for 120 minutes of electrolysis time. From results revealed that Fe.S could be used three times with complete degradation of RB5 from initial concentration of 50 ppm. A complete RB5 colour removal can be achieved in any pH range (3,6, and 9). The current density at 4 mA/cm2 showed a faster RB5 degradation compared to at 2, 6,8, and 10 mA/cm2.

Mechanism underlying visible-light photocatalytic activity of Ag/AgBr: Experimental and theoretical approaches

Reactive Black 5 as electron donor and/or electron acceptor in dual chamber of solar photocatalytic fuel cell

Anaerobic decolorization bacteria for the treatment of azo dye in a sequential anaerobic and aerobic membrane bioreactor

Heterogeneous photo-catalysis system for the degradation of azo dye Reactive Black 5 (RB5)

Reactive black 5 (RB5) is an azo dye widely used in the textile industry for dyeing fabrics. It is categorized as a recalcitrant dye that is hard to degrade and an environmental pollutant. Therefore, textile waste effluents containing this dye must be treated to remove or degrade the dye, before being released into the environment. One method that can be used to degrade synthetic dyes such as RB5 is to use biological methods, by directly using live fungal cells or using laccase enzymes. Trichoderma asperellum LBKURCC1 is a filamentous fungus isolated from cacao plantation soil in Riau, Indonesia, and it is a laccase enzyme producer. To be able to determine the ability of T. asperellum LBKURCC1 life cultures to decolorize RB5 dye, several RB5 dye removal tests were carried out. Incubation of 50 ppm RB5 with life cultures of T. asperellum LBKURCC1 at room temperature (30°C, pH 6.5) for 24 hours resulted in 22% bioremediation, 3.2% biosorption and 19.1% biodegradation of the RB5 dye. The results of this study show that the live culture of T.asperellum LBKURCC1 is capable of biodegrading RB5. This is indicated by the degradation of RB5 by extracellular enzymes produced by these filamentous fungi.