Rhodamine B Removal Research Articles

Co-based MOF heterogeneous catalyst for the efficient degradation of organic dye via peroxymonosulfate activation.

In this study, a new cobalt-based metal-organic framework (JLNU-500), [Co2(OH)(PBA)(AIP)]·3DMA·0.75H2O (4-(pyridin-4-yl) benzoic acid (HPBA), 5-aminoisophthalic acid (H2AIP) and N,N-dimethylacetamide (DMA)), was fabricated using a solvothermal method. JLNU-500 has 3D network architecture with 1D nanopore channels. The prepared JLNU-500 can activate peroxymonosulfate (PMS) for Rhodamine B (RhB) dye decolorization. Interestingly, catalyst JLNU-500 exhibited high efficiency for PMS activation, and nearly 100% (above 99.8%) removal of RhB with a high concentration (50.0 mg L-1, 100 mL) was achieved within 6 min. The reaction rate constant of the JLNU-500/PMS system was 1.02 min-1 calculated based on the pseudo-first-order kinetics, which is higher than that of the other reported catalysts. Furthermore, the factors, which could influence PMS activation were also investigated, such as PMS dosage, catalyst dosage, pollutant RhB concentration, reaction temperature and solution pH. More importantly, the radical trapping experiments ferreted out that sulfate (SO4˙-) and hydroxyl (˙OH) radicals were the dominating oxidants in the removal of RhB. Moreover, the possible degradation mechanism was elucidated. This study provides new prospects for fabricating new MOFs that can potentially be employed for high-efficiency catalytic oxidation as heterogeneous catalysts.

Adsorption of Rhodamine-B Dye by Raw and Activated Bael Leaves: Isotherms, Kinetics and Thermodynamics Perspectives

The agricultural waste and their derived products to remove dyes from wastewater have attracted ample attention due to its availability and economic advantages with high removal efficiency. In this study, raw bael leaves and their prepared carbon were used to remove Rhodamine-B (RhB) dye present in wastewater. The effects of different factors, including concentration (50-100 mg/L), contact time (20-140 min), adsorbent dosage (5-50 mg), pH range (1-10) and temperature (20-60 ºC) were investigated. The maximum percentage removal of RhB dye were found to be 77.4 and 89.9, respectively using raw bael leaves (RBL) and activated carbon of bael leaves (ACBL) with optimum conditions. Different characterization techniques used to characterize the adsorbents (RBL and ACBL) via SEM, FTIR, XRD and BET. Adsorption process obeyed Langmuir isotherm model for both cases viz. adsorption of RhB on RBL and adsorption of RhB on ACBL. The maximum adsorption capacities 86.89 mg/g and 113.82 mg/g were found for RBL and ACBL, respectively. The kinetics adsorption study for adsorption of RhB on RBL and ACBL had a great correlation with pseudo-second order model and confirmed the processes are chemisorption. Therefore, the RBL and ACBL adsorbents could be encouraging adsorbents for the removal of dyes.

Studi Adsorpsi Rhodamin B Menggunakan Silika Sekam Padi

Silica was obtained from rice husk throught an extraction process and applied to remove Rhodamine B (RhB) from aqueous media by adsorption. The better characteristics of the silica were demonstrated by X-ray diffraction, N2 adsorption isotherms and scanning electron microscopy. Silica was used as adsorbent to remove RhB dye in aqueous media. Adsorption kinetics and isotherms were evaluated. Silica presented higher values of surface area, pore volume, pore diameter and porosity. Pseudo-second order was adequate to represent the kinetic profile. The adsorption isotherm follows the Langmuir and Freundlich models. Rice husk silica attained adsorption capacity of 1.06 mg g-1 coupled with removal percentage of 84%, being an excelent adsorbent for RhB dye.

Synthesis, characterization, and DFT investigation of rhodamine B dye removal by activated carbon produced from argan nutshell

A significant environmental concern is posed by wastewater containing dyes. When dealing with a polluted medium, adsorption is a beneficial method for the removal of contaminants. This study used argan nutshell as a precursor to synthesize activated carbon via chemical activation with Na2CO3 at 600 °C. The prepared activated carbon (Na@Ac) was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), and zeta potential measurements. The results showed that the prepared activated carbon has a high surface area (1543 m2/g) and microporous structure. Furthermore, many parameters for Rhodamine B (RhB) dye removal efficiency, including pH, initial pollutant concentration, and temperature, were optimized by response surface methodology (RSM) with a central composite design. Based on the RSM, the best efficiency was 96.84% for the removal of RhB at pH 5, temperature 20 °C, and initial concentration 33.2 mg/L. The kinetic of RhB dye adsorption onto Na@Ac was effectively explained by a pseudo-second-order model, with a maximum uptake capacity of 35.9 mg/g. Moreover, Density functional theory (DFT) calculations were used to understand the adsorption mechanism of the RhB dye onto the Na@Ac. Based on the DFT calculations, hydrogen bonding and π-π interactions may be preferred mechanisms of RhB dye adsorption onto Na@Ac. The Na@Ac could be a promising adsorbent for the removal of Rhodamine B from polluted wastewater.

Activation of peroxymonosulfate by Co-Mg-Fe layered doubled hydroxide for efficient degradation of Rhodamine B.

Reactive species serve as a key to remediate the contamination of refractory organic contaminants in advanced oxidation processes. In this study, a novel heterogeneous catalyst, CoMgFe-LDH layered doubled hydroxide (CoMgFe-LDH), was prepared for an efficient activation of peroxymonosulfate (PMS) to oxidize Rhodamine B (RhB). The characterization results showed that CoMgFe-LDH had a good crystallographic structure. Correspondingly, the CoMgFe-LDH/PMS process exhibited good capacity to remove RhB, which was equivalent to degradation performance as homogeneous Co(II)/PMS process. The RhB oxidation in the CoMgFe-LDH/PMS process was well described with pseudo-first-order kinetic model. Additionally, the oxidation process presented an excellent stability, and only 0.9% leaching rate was detected after six sequential reaction cycles at pH 5.0. The effects of initial pH, CoMgFe-LDH dosage, PMS concentration, RhB concentration, and inorganic anions on the RhB degradation were discussed in detail. Quenching experiments showed that sulfate radicals (SO4•-) acted as the dominant reactive species. Further, the removal of RhB from simulated wastewater was explored. The removal efficiency of RhB (90μM) could reach 94.3% with 0.8g/L of catalyst and 1.2mM of PMS addition at pH 5.0, which indicated the CoMgFe-LDH/PMS process was also effective in degrading RhB in wastewater.

Experimental and theoretical investigations of the photoelectrochemical and photo-Fenton properties of Co-doped FeOCl

For the first time, two-dimensional FeOCl (Fe1−x Co x OCl) doped with Co was successfully applied to the photocatalytic and photo-Fenton degradation of Rhodamine B (RhB). The photocatalytic and photo-Fenton experiments showed that the degradation rates of RhB by Fe0.94Co0.06OCl are 82.6% and 98.2% within 50 min under neutral solution, room temperature and visible light. The inclusion of Co resulted in lattice imperfections on the surface of FeOCl, which was advantageous for the photogenerated electron–hole pair separation efficiency (consistent with the density functional theory calculation). Moreover, the RhB removal rate decreased from 98% to 82% during five successive cycles, showing good structural stability. Finally, based on the radical capture experiment, a potential mechanism for RhB degradation by Fe1−x Co x OCl catalyst was proposed. The idea of a synergistic mechanism for Fe1−x Co x OCl also offers a fresh concept for catalysts used in doping modification.

Efficient Adsorption and Removal of Organic Dyes from Wastewater Using Magnetic UiO-66 Composites

In this study, the magnetic UiO-66 composite was prepared and used as an adsorbent to effectively remove Rhodamine B (RhB) from water. The as-prepared magnetic MOFs composites not only retain the unique structure and properties of MOFs materials, but also can be quickly recovered and separated from aqueous solution by applying a magnetic field. The effects of contact time, initial concentration on the adsorption properties were studied. For RhB, pseudo-second-order model and Langmuir model could well explain the adsorption process of magnetic UiO-66 composite, indicating that the adsorption process of the RhB was mainly performed by chemisorption on uniform surface, and the maximum adsorption capacity is 188.68 mg/g. The possible mechanism for RhB was further proposed, revealing that electrostatic interactions, π-π stacking interactions mainly affected the adsorption process.

Performance and Mechanism of Nanoporous Ni@NiO Composites for RhB Ultrahigh Electro-Catalytic Degradation

Today, the development of new self-supporting electrode materials with high porosity and excellent degradation properties is of great importance for the removal of dye pollutants. Herein, this work synthesized nanoporous nickel@nickel oxide (np-Ni@NiO) electrode containing an amorphous alloy in the middle interlayer. The nanoporous structure endowed the electrode with more active sites and facilitated the ion/electron transport. The electrochemical active surface area was about 185.5 cm2. The electrochemical degradation of rhodamine B (RhB) using a np-Ni@NiO electrode was systematically investigated. The effects of technology paraments (NaCl concentration, the applied potential and pH) on electro-catalytic degradation were explored. An RhB removal rate of 99.68% was achieved in 30 s at optimized conditions, which was attributed to the unique bicontinuous ligament/pore structure and more active sites on the surface, as well as lower charge transfer resistance. In addition, the degradation mechanism of RhB in electrochemical oxidation was proposed, according to active species capture tests and EPR measurements.

Insights into the mechanism of multiple Cu-doped CoFe2O4 nanocatalyst activated peroxymonosulfate for efficient degradation of Rhodamine B

The multiple metal catalyst as a promising nanomaterial has shown excellent activity in the peroxymonosulfate (PMS) activation for pollutant degradation. However, the role of special sites and in-depth understanding of the PMS activation mechanism are not fully studied. In this study, a Cu-doped CoFe2O4 nanocatalyst (0.5CCF) was synthesized by a sol-gel and calcination method, and used for PMS activation to remove Rhodamine B (RhB). The results showed that the Cu doping obviously enhanced the catalytic performance of CoFe2O4, with 99.70% of RhB removed by 0.5CCF while 74.91% in the CoFe2O4 within 15 min. Based on the X-ray photoelectron spectroscopy and electrochemical analysis, this could be ascribed to the more low valence of Co and Fe species generated on the 0.5CCF and faster electron transfers occurred in the 0.5CCF due to the Cu doping. In addition, Cu doping could provide more reaction sites for the 0.5CCF to activate PMS for RhB removal. The metal species and the surface hydroxyl were the reaction sites of PMS activation, and the surface hydroxyl played an important role in surface-bound reactive species generation. During the PMS activation, the Cu not only activated PMS to produce reactive oxygen species (ROS), but also regenerated Co2+ and Fe2+ to accelerate the PMS activation. The non-radical of 1O2 was the main ROS with a 99.35% of contribution rate, and the SO5•– self-reaction was its major source. This study provides a new insight to enhance the PMS activation performance of multiple metal catalysts by Cu doping in wastewater treatment.

Efficient activation of peroxymonosulfate via Cu2+/Cu+ cycle enhanced by hydroxylamine for the degradation of Rhodamine B.

The application of Cu2+/peroxymonosulfate (PMS) process for the elimination of refractory pollutants in industrial wastewater is limited by the slow transformation from Cu2+ to Cu+. In this research, hydroxylamine (HA) was employed to improve the degradation capacity of the Cu2+/PMS process. Rhodamine B (RhB) was selected as the target compound to indicate the performance of HA/Cu2+/PMS process. Compared with the Cu2+/PMS process, the reduction of Cu2+ to Cu+ was effectively promoted by HA in the HA/Cu2+/PMS process, which increased the decomposition rate of PMS by 29.2%, correspondingly, promoted the removal rate of RhB by 77.6%. The degradation of RhB followed pseudo-second-order kinetics in the proposed process. The active species analysis subsequently indicated hydroxyl radicals (·OH) and sulfate radicals (SO4·-) played important roles for degrading RhB with ·OH as the dominant active radical. The effects including initial pH, RhB concentration, PMS concentration, and Cu2+ concentration on the degradation of RhB were further investigated and discussed in detail. Additionally, the HA/Cu2+/PMS process exhibited effective RhB removal in simulated wastewater. From the perspective of waste utilization (Cu2+) and the remediation of organic contamination, the work would provide a valuable and promising process.

Hydrochar from Lansium domesticum and Salacca zalacca Peel as Adsorbent on Rhodamine-B Removal: Adsorption Process and Regeneration Studies

Utilization of duku (Lansium domesticum) peel and salak (Salacca zalacca) peel as rhodamine-B adsorbent was investigated by producing it into hydrochar of duku peel and hydrochar of salak peel by hydrothermal carbonization at 150 °C for 6 hours. XRD shows hydrochar was an amorphous solid (angle of 2ϴ at 30 deg (002)). FTIR characterization of hydrochar showed that hydrochar had the main constituent of the raw material biomass with detected functional groups in the form of -OH, -CH, C=O, and C-O. Wavenumber at FTIR was shifted after adsorption indicated adsorption of rhodamine-B by adsorbent with changes in the structure. Duku peel increased surface area after being hydrochar from 12.343 m2/g to 21.019 m2/g, but salak peel had decreased in surface area from 62.676 m2/g to 23.121 m2/g. The maximum adsorption capacity of duku peel is 58.824 mg/g at 30 °C, HC of duku peel is 114.943 mg/g at 70 °C and salak peel is 92.593 at 30 °C, HC of salak peel is 102.041 mg/g at 30 °C. In this study, the adsorption kinetics and isotherm models follow the PSO kinetic model and Langmuir isotherm with an endothermic and spontaneous adsorption process. Adsorption efficiency in the regeneration process increases from fruit peel to hydrochar and can be used repeatedly in the regeneration process for 3 cycles.

Photocatalysis performance enhancement of Ag2O/Al-doped ZnO heterojunction by introducing ZnO nanorod array

Fabric-based nano semiconductor photocatalysts have attracted much attention in recent years. In this study, polyester fibers were modified by Ag2O/ZnO nanorod (NR)/Al-ZnO p-type/high resistivity/n-type (P-HR-N) heterojunction arrays. Al-doped ZnO (Al-ZnO) seed layer was reactively sputtered on polyester fibers. Al doping was used to change the work function (WF) of the ZnO film. The ZnO NR arrays were hydrothermally grown on the Al-ZnO seed layer and modified with Ag2O film. The work functions (WFs) of Ag2O and Al-ZnO layers were measured, resulting in 5.53 and 4.81eV, respectively. The WF difference between the two layers was 0.72eV. The electron-hole separation of the P-HR-N heterojunction array was characterized by surface photovoltage (SPV) spectra. The photocatalytic activities of the prepared samples were investigated by removing Rhodamine B (RB) under UV irradiation. The P-HR-N heterojunction sample displayed a better photocatalytic performance than the Ag2O/Al-doped ZnO PN heterojunction sample and ZnO NR/Al-ZnO array-coated sample. The enhanced photocatalytic performance of the P-HR-N heterojunction based sample was mainly attributed to the high and widened built-in electric field (BEF) in the multilayer film.

Construction of activated biochar/Bi2WO6 and /Bi2MoO6 composites to enhance adsorption and photocatalysis performance for efficient application in the removal of pollutants and disinfection.

To synergistically enhance the adsorption and photocatalytic performance of Bi2WO6 and Bi2MoO6, using activated biochar (ACB) as substrate, ACB-Bi2WO6 and ACB-Bi2MoO6 composites were facilely prepared by hydrothermal synthesis. Their adsorption-photocatalytic degradation effects on rhodamine B (RhB), tetracycline (TC), and norfloxacin (NOR) were comparatively investigated. Additionally, the effects of environmental factors, wastewater treatment tests, and disinfection were systematically studied, and the enhancement mechanisms and reasons for the degradation differences were highlighted. The results showed that ACB-Bi2WO6 and ACB-Bi2MoO6 were confirmed to form intimately contacted heterojunctions by various advanced characterization techniques. The introduction of ACB narrowed the band-gap energy of Bi2WO6 and Bi2MoO6, and improved the visible light absorption range and specific surface area. The optimal loading ratios of ACB-Bi2WO6 and ACB-Bi2MoO6 were 1:1.06 and 1:0.58, respectively. The removal rate of ACB-Bi2WO6 for high concentrations of RhB (200 mg·L-1), TC and NOR (50 mg·L-1) were 89.15%, 87.27%, and 72.17%, respectively, which were higher than those of ACB-Bi2MoO6 and significantly stronger than those of Bi2WO6 and Bi2MoO6. This was attributed to the more effective inhibition of photogenerated carrier recombination, higher absorbance, and uniform morphology via ACB-Bi2WO6. ·OH and holes were dominant active species in photocatalysis, and the possible photogenerated carrier transfer path is type II heterojunction. Furthermore, ACB-Bi2WO6 possessed good reusability, and the removal of RhB and TC from the actual wastewater exceeded 80.63% and 58.54%, respectively. The sterilization rates of ACB-Bi2WO6 reached 99% and 95% for E. coli and S. aureus within 24 h, respectively. Therefore, ACB-Bi2WO6 was more recommended for environmental applications.

Ultrasound-enhanced catalytic degradation of simulated dye wastewater using waste printed circuit boards: catalytic performance and artificial neuron network-based simulation.

Recent developments of heterogeneous advanced oxidation for refractory organic contaminants and catalysts made of solid waste have attracted much attention. In this work, waste printed circuit board (wPCB) was used for catalytic degradation of simulated textile wastewater enhanced by ultrasound. Catalytic degradation of rhodamine B (RhB) and methylene blue (MB) was conducted in the presence of H2O2. Effect of ultrasound, wPCB, H2O2, pH, and dye concentration was investigated by single factor experiments. The growing catalytic efficiency was determined by ultrasound. The removal efficiency of MB and RhB are influenced by wPCB, H2O2, pH, and dye concentration. Degradation efficiency is accelerated with increasing wPCB dosage and H2O2 and decreasing dye concentration. Effective degradation of MB and RhB is obtained under broader pH region, attractively at neutral pH. Under optimal conditions, MB removal reaches 98.83% at 90min while RhB removal reaches 99.57% at 80min. Hydroxyl radicals play an important role in catalytic process. Tentative mechanism for catalytic degradation of MB and RhB are discussed based on multiple characterizations. Superior reusability of wPCB proves that wPCB is highly durable catalyst. Due to low cost and high efficiency, wPCB is attractive as effective catalyst for treatment of organic wastewater. Artificial neuron network-based (ANN) simulation, as a widely used artificial intelligence algorithm, was one of preferred methods for the wastewater treatment due to its unique properties in solving complex processes. An ANN model was designed for the prediction of the performance of ultrasound-enhanced catalytic degradation with a high R value (0.99).

Multi-dimensional (2D–3D) assembly of BiOI/BiOBr/UiO-66-NH2 composites to form multi-heterojunction structures for synergistic removal of Rhodamine B

In order to enhance the role of UiO-66-NH2 in the photocatalytic system, the method of loading Bi-based materials to construct heterojunctions was chosen to enhance its photocatalytic ability. In this study, the ternary composite BiOI/BiOBr/UiO-66-NH2 was successfully synthesized, and a double type Ⅱ heterojunction was formed among the three. The successful synthesis and the closely interaction of the composites were proved by a series of characterization. Under simulated visible light, the composite material (UBB3) with a molar ratio of KBr to KI of 1:3 had the best RhB removal performance. The removal rate of Rhodamine B (RhB) can be as high as 99.16 % after 80 min of visible light irradiation. This study also preliminarily explored the direct, efficient and rapid degradation of RhB under visible light without dark adsorption stage. The composite material also had good reusability. The enhancement of visible light utilization and the inhibition of electron(e-)-hole(h+) recombination were the main reasons for the enhancement of photocatalytic activity. In the presence of double heterojunctions, it was found that while the formation of superoxide radicals was involved in the degradation of pollutants, h+ were directly involved in the degradation of RhB as reactants, reducing the reaction procedure. Finally, the photocatalytic mechanism was proposed.

Oxygen-vacancy abundant electrospun Co-doped Ruddlesden-Popper perovskite catalysts for peroxymonosulfate activation and Rhodamine B degradation

The versatility of perovskite crystal structures has allowed their application in persulfate-based advanced oxidation process (PS-AOP). In this study, novel agglomerated-free Ruddlesden-Popper (RP)-type perovskite catalysts were fabricated via electrospinning and subsequent annealing. Structure modulation strategy was implemented by a moderate Co-substitution of relatively inert Cu at B site of RP-type La2CuO4. The performances of Co-doped perovskites (Cox-LC1-xO) for peroxymonosulfate activation and Rhodamine B (RhB) removal were investigated. Co displacement altered the Cox-LC1-xO compositions, increased the concentration of oxygen vacancies (OVs) and accelerated the electron transfer, thereby causing complementary effects on catalytic activities. The abundant OVs governed the production of reactive oxygen species (ROS) by regulating the cationic redox cycle and decreasing the energy barrier for PMS activation. In particular, OVs energized lattice oxygen, allowing RhB degradation by Co0.5-LC0.5O via the 1O2-dominant non-radical pathway. Co0.5-LC0.5O outperformed other Cox-LC1-xO catalysts with regard to RhB removal efficiency (∼98% within 30 min) and reaction kinetics (k = 0.552 min−1). Besides, Co0.5-LC0.5O exhibited decent reusability, wide pH range (4.0–8.5), and saline adaptation. These findings may facilitate the design of analogous peroxymonosulfate catalysts for wastewater reclamation.

Biosynthesis of gold nanoparticles using ethanolic propolis extract for methylene blue and Rhodamine-B removal

• The green synthesis of gold nanoparticles (AuNPs) was done by propolis extract. • Photocatalytic degradation was performed using AuNPs under UV light. • AuNPs showed significant efficiency for methylene blue and Rhodamine B. The study proposed that gold nanoparticles (AuNPs) that were biosynthesized using propolis extract can degrade methylene blue (MB) and Rhodamine-B. First, the AuNPs were characterized using color change, electron microscopy, vis-UV spectroscopy, and Fourier-transform infrared (FTIR) analysis; then, the photocatalytic activity was measured under U.V. in various concentrations. The results showed a color change from yellowish to violet, indicating the reduction of Au 3+ to Au 0 . In addition, transmission electron microscopy (TEM) showed that the polydispersed shapes were in the nanoscale. Moreover, the biosynthesized AuNPs have high removal efficiency for MB and Rhodamine-B under U.V. irradiations. The implications of these findings proposed a new and sustainable method for the biosynthesis of AuNPs using the ethanolic propolis extract with the promising potential for removing contaminants in water.

Facile synthesis of Tri-metallic layered double hydroxides (NiZnAl-LDHs): Adsorption of Rhodamine-B and methyl orange from water

In this research work, tri-metallic layered double hydroxides (NiZnAl-LDH) nano-sheets were efficiently synthesized by hydrothermal technique and applied for the decontamination of rhodamine B (Rh-B) and methyl orange (MO). Material characterizations confirm the formation of tri-metallic NiZnAl-LDH nano-sheets of continuous macrostructure skeleton with interconnected macropores. Several adsorption factors like initial concentration, pH of dyes solution, contact time and adsorbent dosage were investigated. Results exposed that synthesized NiZnAl-LDH perform best in basic medium for the removal of Rh-B and in mild acidic for that of MO. Also with 210 min contact time NiZnAl-LDH showed adsorption efficiency of 38.03 mg/g for Rh-B and 32.67 mg/g for that of MO. The Langmuir model perfectly defined the adsorption process on to the surface of NiZnAl-LDH as monolayer with relatively higher R2 value (R2 = 0.978 for Rh-B and 0.996 for MO). The maximum adsorption capacities (qmax) calculated with Langmuir model were 97.09 mg/g for Rh-B and 105.26 mg/g for MO, which are analogous with other conventional adsorbents. Furthermore, the adsorption of Rh-B and MO onto NiZnAl-LDH follow pseudo second order kinetics indicating that adsorption process is independent to that of concentration of adsorbate. Additionally, reusability experiment confirmed that the fabricated tri-metallic LDHs nano-sheets own outstanding recyclability with qe = 21.25 mg/g of Rh-B and 28.55 mg/g of MO at 4th regeneration cycle. The outcomes of this research could serve as a foundation for designing and engineering exceptional materials for purification of industrial waste water.

Removal of Synthetic Dye from Aqueous Solution Using MnFe2O4-GO Catalyzed Heterogeneous Electro-Fenton Process

In the present study, heterogeneous electro-Fenton (HEF) process using MnFe2O4-GO catalyst is employed for the successful removal of dye from aqueous solution. Pt coated over titanium and graphite felt were used as the electrodes. The study focuses on the efficiency of the electrodes and catalyst used for the successful removal of Rhodamine B (RhB) from aqueous solution and the application of the same in real textile wastewater. The effect of various operational parameters like pH, applied voltage, catalyst concentration, initial pollutant concentration and effect of ions were investigated. The optimized condition of the electrolytic system was found as pH 3, applied voltage of 3 V, and catalyst concentration of 20 mg L−1 for the removal of 10 ppm RhB. At the optimized condition, 97.51% ± 0.0002 RhB removal was obtained after an electrolysis time of 60 min. The role of individual systems of Fe, Mn, GO and MnFe2O4 without support were compared with that of catalyst composite. On examining the practical viability in real textile effluent, a significant colour reduction was observed (reduced by 61.24% ± 0.0261 in 60 min). Along with this, the biodegradability enhancement (BOD/COD ratio from 0.07 to 0.21) after treatment was also observed.

Application of liquid film dielectric barrier discharge plasma reactor in the degradation of rhodamine B: Performance optimization, mechanism and pathways

In the present work, the degradation pathways and mechanism of rhodamine B (RhB) using a novel liquid film dielectric barrier discharge (DBD) plasma reactor were examined. Moreover, the optimization of the performance of DBD was discussed. The results showed that the atmosphere of the discharge area and the input power had a significant effect on the removal of RhB. After 21 min of treatment using DBD plasma system, about 90.2 % of RhB was degraded under the following experimental conditions: initial RhB concentration of 40 mg/L; input power of 125 W and initial pH of 6.78. The use of free radical scavengers proved that hydroxyl radicals played a key role in the degradation of RhB. In addition, the degradation intermediates of RhB were identified using liquid chromatography mass spectrometry, and possible degradation pathways were proposed. During the degradation of RhB, with the extension of treatment time, the values of COD, BOD5 and TOC decreased. After the treatment using DBD plasma, the BOD5/COD of RhB solution increased from 0.0326 to 0.3867, and the biodegradability was also observed to have greatly improved. The potential toxicity was predicted by US-EPA-TEST software.