Decolorization Rate Research Articles

Study of Adsorption Kinetics of Fe Metal in Batik Cual Waste using Chitosan of Rice Crab Shells

Fe metal is one of the heavy metal composition contained in cual batik waste. The content of these metal has potency as pollutan and can increase the risk of chemical substance stored in various aquatic biota and very dangerous for human consumption because it is toxic in the long term. In this research, batik waste treatment has been carried out by decadarizing Fe metal using adsorbent agent based from citosan. Paddy crab shell was extracted through demineralization, deproteination, decolorization, and deacetylation to become chitosan powder. Chitosan powder becomes an adsorbent in the adsorption process with adsorption data collection patterns for various contact times of 30, 60, 90, 120, 150, 180, 210, and 240 minutes. The adsorption results were kinetic modeled using the kinetic model of first order, second order, and BMG. From that three models obtained the R2 value that is closest to 1 is the BMG kinetic model, which is 0.999602. In addition, this model has the advantage that is it can find out the magnitude of the decolorization decay constant and the rate of decolorization of Fe metal.

Process optimization of malachite green degradation by mixed biofilm positive bacteria: Application of Box–Behnken designs, RSM and whole genome sequences analysis

Bacterial biofilm positive strains recovered from engine oil polluted-soil was investigated for its capacity to remove malachite green (MG) in mineral salt solution. Box–Behnken designs combining four factors (glucose, yeast extract, temperature and agitation) with three levels (−1, 0, +1) was used to found the best biotic and abiotic conditions for MG removal. The biodegradation potential of the selected microbial consortium was also confirmed using analytical techniques. Then, whole genome sequencing (WGS) analysis were performed to detect genes related to biofilm formation and chemicals biodegradation. Our results showed that the selected strains (G5, G13 and G15) were able to form biofilm on congo red agar plates developing almost black, very black and almost black colonies respectively. Experimental results using Box-Behnken designs showed that decolorization rate of MG reach 89.35% in these optimized conditions: glucose (2%), yeast extract (1%), temperature (40 °C), and agitation (150 rpm). Molecular investigation revealed that the isolated strains were identified as Cronobacter sakazakii G5, Enterobacter hormaechei G13, and Klebsiella pneumoniae G15 based on the whole genome sequences . Whole genome sequences analysis demonstrated the presence of genes involved in biofilm formation as well as dyes and chemical detoxification. The findings presented here provide useful information for development an efficient microbial consortium, formed by adherent bacteria, able to remove dye from coloured wastewater.

Statistical optimization of Congo red biodegradation by a bacterial strain of Alcaligenes faecalis

The textile industry consumes a significant amount of water and chemicals, with a primary visible chemical pollutant being a dye that poses dangers to humans and aquatic life. In order to tackle this issue, bacterial isolates from textile effluent were screened to assess their ability to degrade Congo red (CR) dye. The decolorization process was optimized using response surface methodology (RSM) based on the Box-Behnken design (BBD). The RSM response optimizer prediction revealed the remarkable efficiency of Alcaligenes faecalis H77 (accession number OK353795), a bacterial strain identified through 16S rRNA sequencing, in decolorizing CR dye. The analysis showed an impressive decolorization rate of 92.51 % for a concentration of 25 mg/L during 72 h, at pH 6.7 and 35 °C. The degradation of the dye was confirmed through liquid mass chromatography-mass spectra analysis, which also indicated the production of less toxic byproducts during the biodegradation process, as identified by LC/MS analysis. In conclusion, Alcaligenes faecalis H77 proved to be highly effective in biodegrading CR, and the statistical modeling employed successfully maximized the efficiency of the biodegradation process.

Expansion of carbon source utilization range of Shewanella oneidensis for efficient azo dye wastewater treatment through co-culture with Lactobacillus plantarum.

Shewanella oneidensis has demonstrated excellent potential for azo dye decolorization and degradation. However, in anaerobic environments, S. oneidensis has a narrow carbon source spectrum, which requires additional electron donors, such as sodium lactate. This increases the practical application costs for wastewater treatment. Here, we aimed to expand the carbon source utilization range of S. oneidensis FJAT-2478 by co-culturing it with Lactobacillus plantarum FJAT-7926, leveraging their commensalism relationship to develop a metabolic chain. Results showed that a 1:2 initial ratio of L. plantarum FJAT-7926 to S. oneidensis FJAT-2478 achieved a 97.16% decolorization rate of methyl orange when glucose served as the sole carbon source. This co-culture system achieved a decolorization rate comparable to that obtained using sodium lactate as an electron donor and was significantly higher than that achieved by L. plantarum FJAT-7926 (7.88%) or S. oneidensis FJAT-2478 (6.89%) alone. After undergoing five cycles, the co-culture system continued to exhibit effective decolorization. It was demonstrated that the co-culture system could use common and inexpensive carbon sources, such as starch, molasses, sucrose, and maltose, to decolorize azo dyes. For instance, 100mg/L methyl orange could be degraded by over 98.05% within 24h. The results indicated that the degradation rates of methyl orange were higher when L. plantarum was inoculated first, followed by a subsequent inoculation of S. oneidensis after 2h. The co-culturing of L. plantarum FJAT-7926 and S. oneidensis FJAT-2478 proved to be an effective strategy in treating azo dye wastewater, expanding the potential practical applications of S. oneidensis.

Effect of Current Density on the Corrosion Resistance and Photocatalytic Properties of Cu-Ni-Zn0.96Ni0.02Cu0.02O Nanocomposite Coatings.

2 at.% Cu + 2 at.% Ni were co-doped in ZnO nanoparticles by a simple hydrothermal method, and then the modified nanoparticles were compounded into Cu-Ni alloy coatings using an electroplating technique. The effects of the current density (15-45 mA/cm2) on the phase structure, surface morphology, thickness, microhardness, corrosion resistance, and photocatalytic properties of the coatings were investigated. The results show that the Cu-Ni-Zn0.96Ni0.02Cu0.02O nanocomposite coatings had the highest compactness and the best overall performance at a current density of 35 mA/cm2. At this point, the co-deposition rate reached its maximum, resulting in the deposition of more Zn0.96Ni0.02Cu0.02O nanoparticles in the coating. More nanoparticles were dispersed in the coating with a better particle strengthening effect, which resulted in a minimum crystallite size of 15.21 nm and a maximum microhardness of 558 HV. Moreover, the surface structure of the coatings became finer and denser. Therefore, the corrosion resistance was significantly improved with a corrosion current density of 2.21 × 10-3 mA/cm2, and the charge transfer resistance was up to 20.98 kΩ·cm2. The maximum decolorization rate of the rhodamine B solution was 24.08% under ultraviolet light irradiation for 5 h. The improvement in the comprehensive performance was mainly attributed to the greater concentration of Zn0.96Ni0.02Cu0.02O nanoparticles in the coating, which played the role of the particle-reinforced phase and reduced the microstructure defects.

Sulfur deficiency mediated visible emission of ZnS QDs by magnesium dopant and their application in waste water treatment

The photocatalyst with antimicrobial activity serves as a better candidate material for wastewater treatment, as wastewater contains microbes, hazardous dyes, and heavy metals. Hence, the present study extensively examines the photocatalytic and antibacterial activities against two waterborne bacterial strains, namely Salmonella typhi and Escherichia coli. Pure and Mg-doped ZnS (Mg:ZnS) quantum dots (QDs) were synthesized using a low-cost and simple co-precipitation method. The QDs' structural, surface morphology, chemical purity, and optical characteristics were analyzed through XRD, SEM, EDAX, TEM, UV–visible, and photoluminescence spectra. The incorporation of Mg dopants did not introduce significant alterations to the cubic blende structure of ZnS, nor did it induce substantial changes in the structural parameters. However, the QDs exhibited a slight sulfur deficiency, which was further increased by the presence of Mg dopant. The Mg dopant, due to its dominant compositional effect, reduced the band gap. Several optical emission bands were observed in the UV, violet, blue, and green regions, corresponding to NBE emission, sulfur-related defects, and Zn-related defects. Initially, Mg doping enhanced visible emission related to defects, while NBE emission was suppressed by the Mg dopant. However, increasing the concentration of the Mg dopant led to a slight increase in NBE emission. The Mg dopant enhanced the photocatalytic activity of the QDs, and a strong correlation was found between photocatalytic activity and NBE emission. The presence of the Mg dopant led to an increased rate of ROS-based decolorization by reducing the electron-hole recombination rate.

Application of Hydrogen-Based Denitrification: Simultaneous Removal of Nitrate and Reactive Black 5 Dye from Textile Wastewater Containing Organic Matter

In this study, a hydrogen-based denitrification (HD) reactor was used to investigate the simultaneous treatment of nitrogen and decolorization in textile wastewater contaminated with organic matter. The reactor operated in two phases: without and with organic matter. Despite the short hydraulic retention time, the HD system successfully removed all pollutants, including nitrate, nitrite, reactive black-5 dye and chemical oxygen demand. The unhindered treatment efficiency for nitrogen and decolorization in the presence of organic pollutants was observed. With the addition of organic matter, the nitrogen removal efficiency increased slightly from 85% to 90–100%, and the decolorization rate doubled from 25% to 50–60%. Organic matter played a crucial role in stimulating heterotrophic bacteria during biological denitrification and acted as a carbon source facilitating biological denitrification and azo bond cleavage during dye degradation. Despite the generation of toxic byproducts and changes in the dominant microbial community, the treatment efficiency remained stable and improved. This approach offers a promising solution for enhancing treatment efficiency in textile wastewater, providing a cost-effective and environmentally friendly option for developing countries to treat wastewater before discharge.

Solar-light-sensitive applications of recycled iron oxyhydroxide as photoelectrolytic heterostructure by encapsulating in reduced graphene oxide and titanium oxide nanotube array (FeOxrGO/TiNTA)

FeOxrGO/Ti photoanodes by decorating TiO2 nanotube array (TiNTA) with waste iron oxide and reduced graphene oxide (rGO) were synthesized via wet impregnation and calcination. Photoelectrocatalytic (PEC) degradation of azo dye pollutants, accompanied by hydrogen gas evolution, was demonstrated in a dual-chamber divided cell. Characterization showed that the iron oxide recovered from the wastewater treatment plant were crystalline clusters consisting of mineral goethite nanoparticles (αFeOOH NPs) with a visible-light responsive bandgap. Furthermore, the incorporation of rGO led to an enhancement in the electrochemical surface area (ECSA, cm2) of the anode due to its larger capacitive current compared to TiNTA. This improvement facilitated the transport of charge carriers (e- and h+) within a type-II heterostructure of αFeOOH and TiO2. The applied bias photon-to-current conversion efficiency and transient photocurrent density, depending on the composition of iron oxide in FeOxrGO/Ti, substantially increased. 2%wt of iron oxide in FeO2.0rGO/Ti has been optimized in terms of azo dye decolorization, TOC removal, and H2 generation rates (on Pt/G cathode) in 0.1 M Na2SO4 at a working potential of +1.0 V (vs. Ag/AgCl). This study explored the reusability and valorization of Fenton fluidized-bed waste iron oxide with TiO2 for PEC applications.

Evaluating the efficacy of wood decay fungi and synthetic fungal consortia for simultaneous decolorization of multiple textile dyes.

Wastewater from the textile industry dyeing process containing high loads of synthetic dyes leads to pollution of water with these toxic and genotoxic dyes. Much effort has been put towards developing biological systems to resolve this issue. Mycoremediation is a well-known approach using fungi to remove, degrade, or remediate pollutants and can be applied to decolorize textile dyes in industrial effluent. Fungal strains from four genera of Polyporales, namely Coriolopsis sp. TBRC 2756, Fomitopsis pinicola TBRC-BCC 30881, Rigidoporus vinctus TBRC 6770, and Trametes pocas TBRC-BCC 18705, were studied for decolorization efficiency, and R. vinctus was found to exhibit the greatest activity in removing all seven tested reactive dyes and one acid dye with a decolorization efficiency of 80% or more within 7 days under limited oxygen. This fungus simultaneously degraded multiple dyes in synthetic wastewater as well as industrial effluent from the dyeing process. To enhance the decolorization rate, various fungal consortia were formulated for testing. However, these consortia only trivially improved efficiency compared with using R. vinctus TBRC 6770 alone. Evaluation of R. vinctus TBRC 6770 decolorization ability was further performed in a 15-L bioreactor to test its ability to eliminate multiple dyes from industrial effluent. The fungus took 45 days to adapt to growth in the bioreactor and subsequently reduced dye concentration to less than 10% of the initial concentration. The following six cycles required only 4-7 days to reduce dye concentrations to less than 25%, demonstrating that the system can run efficiently for multiple cycles without the need for extra medium or other carbon sources.

Expression of a deep-sea bacterial laccase from Halomonas alkaliantartica and its application in dyes decolorization

IntroductionLaccase is a copper-containing polyphenolic oxidase widely found in bacteria, archaea, fungi, animals, and plants. As a green biocatalyst with considerable potential for numerous environmental and industrial applications, the enzyme production efficiency of laccase in nature is low, and the cost is high.PurposeTo examine the characterization and potential applications of laccase in this study, a novel laccase from Halomonas alkaliantartica (LacHa) was cloned and heterologously expressed it in Escherichia coli.ResultsTo achieve heterologous and efficient laccase expression, a bacterial laccase gene designed as LacHa from Halomonas alkaliantartica of deep sea was cloned and expressed in E. coli. The results showed that the optimum temperature and pH of the enzyme reaction were 45 °C and 7.5. The 100 μM Cu2+ and Fe2+ ions had the strongest stimulatory effect on laccase activity, the surface-active agent SDS and organic solvent 5% ethanol had opposite effect. EDTA, and 5% DMSO have no effect on LacHa activity.The activity of LacHa was enhanced 1.5-fold by chloride at concentrations lower than 500 mM, and 57.6% of its initial activity remained in the reaction system containing 1000 mM.NaCl. Furthermore, LacHa showed decolorization rates ranging from 90.28 to 100% for indigo carmine and two azo dyes without mediators, with wide pH (5.0–9.0) and temperature (25–65 °C) ranges.ConclusionsIn this study, LacHa was expressed and showed unusual properties, indicating its great application potential in textile industries or environmental fields.

Synthesis of a Novel Photocatalyst Based on Silicotitanate Nanoparticles for the Removal of Some Organic Matter from Polluted Water

The use of waste from various agricultural sectors has recently drawn increased interest from the scientific, technological, ecological, economic, and social fields. As such, in this study, a novel production of an affordable and environmentally friendly photocatalyst of silicotitanate (S1, S2, and S3) made from silica solution (extracted from rice husk ash) and various molar ratios of titanium (IV) 2-ethylhexyl-oxide is reported. Following that, chitosan/silicotitanate (CHMix) nanocomposite material was created through a crosslinking reaction between chitosan and fabricated silicotitanate (S2). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), as well as N2 adsorption-desorption isotherm and zeta potential measurements were used to characterize each of the fabricated samples. Additionally, in comparison to neat chitosan, the newly fabricated material’s (CHMix) photocatalytic reactivity was investigated using two synthetic anionic dyes, reactive blue and Congo red, with decolorization rates of up to 95.76% and 99.9%, respectively. The decolorization results showed that CHMix is the most efficient photocatalyst for the degradation of reactive blue and Congo red. Reactive blue and Congo red’s molecular structures were almost completely broken when equilibrium was reached using sunlight, and the decolorization rate for both dyes was close to 100%. As a result, the combination of chitosan and silicotitanate, or CHMix, has an effective photocatalytic capability for dye degradation in both natural and concentrated sunlight.

Comparative Advanced Oxidation Decolorization of the Triphenylmethane Dye with Dimethyl Dioxirane and Hydrogen Peroxide

Methyl Violet (MV), a triphenylmethane dye, has been subjected to comparative studies with hydrogen peroxide and dimethyl dioxirane under optimum situations. When employing hydrogen peroxide, the photolysis process becomes slower, but the dye solutions are entirely decolored and mineralized. The decolorization rate exhibits pseudo-first-order kinetics. The effect of pH, oxidant dosage, and methyl violet concentration on the degradation is also examined. Generated o-leucoaniline,1,3-diphenylurea,2-hydroxy benzoic acid, phenol, acetone, water, carbon dioxide, and carbon monoxide are identified and measured by GC-MS analysis. These substances remain in the dye solution along with dimethyl dioxirane, which is released faster during the last stages of degradation. The degradation rates of methyl violet reached 97.9% and 65.8% within 30 mins and 180 min of reaction time using dimethyl dioxirane and hydrogen peroxide.

Fabrication of New TiO2 Photocatalyst for Removing Organic Dyes and Hazardous VOCs in Air Purifier System

We synthesized an amorphous Ti-based hydroperoxo complex (ATPC) using a facile method involvingonly titanium hydride (TiH2) and H2O2 under mild conditions. We chose TiH2 as the precursor because it has more reactive sites than metal oxides such as TiO2. Qualitative and quantitative optical measurements showed that our synthesized ATPC photocatalysts contained many hydroperoxo groups and various oxidation states of Ti (Ti2+, Ti3+, and Ti4+). Thus, the synthesized ATPC exhibits excellent photocatalytic properties with very fast rates of organic decolorization compared to other conventional visiblelight catalysts. The presence of many hydroperoxo complexes increases the formation of active radicals, which can degrade VOCs such as acetaldehyde in a gas phase. To test the application of the synthesized ATPC, we fabricated a filter system in an air purifier using ATPC coating layers and successfully removed the VOCs. We also proposed a possible photocatalytic oxidation mechanism with ATPC based on this study. It is important to conduct application tests as well as commercialization in photocatalytic experiments.

Synthesis, Characterization, and application of Ag-Doped Mercapto-Functionalized clay for decolorization of Coomassie brilliant Blue: Optimization using RSM

Herein, we report the use of silver nanoparticles (AgNPs) supported on mercapto-functionalized clay for the decolorization of Coomassie brilliant blue (CBB). The effect of four parameters (NaBH4 amount, CBB concentration, time, and catalyst amount) on the decolorization efficiency and the optimization of the process was investigated. Under optimum conditions (8.76 mM, 20.86 mg/L, 115.82 s and 0.23 mg/mL for NaBH4 amount, CBB concentration, time, and catalyst amount, respectively), the decolorization efficiency for CBB was 97.73%. The kinetic results indicated decolorization rate was increased toward the temperature (293 to 323 K). The thermodynamic parameters show that the process is endothermic and favorable.

Self-organization towards complex meso-helix in the structures of keggin-type polyoxometalate-based metal-organic frameworks for photocatalytic degradation of rhodamine B

For exploring the V-shape organic ligand influence on the fabrication of complex helices or meso-helices in polyoxometalate-based metal-organic frameworks (POMOFs), a crystalline hybrid with intricate meso-helix structure, H [K2Ag9(DPT)7 (u-2-O)2(H2O)4][SiW12O40]2 (1) {DPT = 2,5-di (pyridin-3-yl)-1,3,4-thiadiazole}, was successfully isolated under hydrothermal conditions. Compound 1 displays a complex meso-helix which is composed of two types of metal-organic subunits. Subunit A, is a non-planar S-shaped metal-organic chain that is constructed by five DPT ligands and four Ag cations, and subunit B is a planar S-shaped metal-organic unit that is built by two DPT ligands and three Ag cations. Further, subunit A and B are fused together in the A-B-A-B mode to generate an unprecedented meso-helix. The photocatalytic performance of compound 1 was evaluated by the RhB decorlorization. Under the UV light irradiation, the photocatalytic decolorization rate of RhB is 75.9% within 300 min, which is 1.82 times than pure (NBu4)4 [SiW12O40]. The cycle experiment shows that title compound has excellent stability after 5 cycles. In addition, the possible mechanism of the photocatalytic degradation has been fully discussed.

Decolorization of Melanoidin Using Sono–Fenton and Photo–Fenton Processes

Ethanol production wastewater contains high quantities of dark–brown pigments (melanoidin) that result in low color removal using conventional biological treatments. Advanced oxidation processes (AOPs) are the most documented methods for reducing the color associated with melanoidin. This study examines the degradation of melanoidin using AOPs based on photo–Fenton, sono–Fenton, and sono–photo–Fenton processes. Their effects on decolorization were investigated based on light intensity, ultrasonic frequency, and the iron concentration (Fe2+)–to–H2O2 ratio. This study showed that ultrasonic waves and UV light result in a higher melanoidin decolorization efficiency than Fenton reactions alone. The initial color values were reduced from 5000–5500 ADMI to below 500 ADMI for both processes because the ultrasonic waves and ultraviolet light induced H2O2 breakdown into the 🞄OH radical. Reducing the color of the melanoidin using the photo–Fenton process resulted in a decolorization rate of 0.1126 min−1, which was higher than the rates of both the sono–Fenton and sono–photo–Fenton processes. These results provide proof that the photo–assisted Fenton process is more applicable to treating dye–contaminated water than are other enhancing approaches.

Fabrication of modified electrode by reduced graphene oxide (rGO) and polyaniline (PANI) for enhancing azo dye decolorization in bio-electrochemical systems (BESs)

Bio-electrochemical systems (BESs) have attracted wide attention in the field of wastewater treatment owing to their fast electron transfer rate and high performance. Unfortunately, the low electro-chemical activity of carbonaceous materials commonly used in BESs remains a bottleneck for their practical applications. Especially, for refractory pollutants remediation, the efficiency is largely limited by the cathode property in term of (bio)-electrochemical reduction of highly oxidized functional groups. Herein, a reduced graphene oxide (rGO) and polyaniline (PANI) modified electrode was fabricated via two-step electro-deposition using carbon brush as raw material. Benefiting from the modified graphene sheets and PANI nanoparticles, the rGO/PANI electrode shows highly conductive network with the electro-active surface area increased by 12 times (0.013 mF cm−2) and the charge transfer resistance decreased by 92% (0.23Ω) comparing with the unmodified one. Most importantly, the rGO/PANI electrode used as abiotic cathode achieves highly efficient azo dye removal from wastewater. The highest decolorization efficiency reaches 96 ± 0.03% within 24 h and the maximum decolorization rate is as high as 20.9 ± 1.45 g h−1·m−3. The features of improved electro-chemical activity and enhanced pollutant removal efficiency provide a new insight toward development of high performance BESs via electrode modification for practical application.

In situ encapsulation of laccase in mesoporous amorphous ZIF-8 for Reactive Blue 19 removal.

Laccase with substrate non-specificity is particularly effective in pollutant degradation. However, the practical application of the laccase is limited due to its poor stability and reusability. In this study, a simple in situ encapsulation method was used to immobilize laccase into amorphous zeolitic imidazolate frameworks-8 (aZIF-8), and the synthesized Lac@aZIF-8 biocomposites were used to remove Reactive Blue 19 (RB 19). Results indicated that the presence of mesoporous endowed the immobilized laccase with higher substrate affinity. Compared with free laccase, the Lac@aZIF-8 showed higher thermo-tolerant performance, wider pH range, better storage stability, and reusability. The Lac@aZIF-8 biocomposites have excellent performance in the effective removal of RB 19. Without any mediators, the dye decolorization rate of immobilized laccase reached up to 82% in 3h under optimal conditions. Based on the LC-MS analysis, the proposed degradation pathways of RB 19 were discussed technically. Moreover, the growth inhibition experiments on Scenedesmus obliquus confirmed the lower toxicity intensity of the degradation products. This research enhanced the stability of laccase while maintaining high substrate affinity, providing a novel strategy for the green and efficient treatment of dye wastewater. PRACTITIONERS POINTS: Lac@aZIF-8 was synthesized by a simple in situ encapsulation method. The mesoporous structure endows the immobilized laccase with higher substrate affinity. The Lac@aZIF-8 shows higher thermo-tolerant performance, wider pH range, better storage stability, and reusability. The Lac@aZIF-8 biocomposites have excellent performance in RB 19 removal.

Methylene Blue biodecolorization and biodegradation by immobilized mixed cultures of Trichoderma viride and Ralstonia pickettii into SA-PVA-Bentonite matrix

The problem of industrial dye wastewater poses a critical environmental challenge that demands urgent attention. This is because the direct release of synthetic dyes such as Methylene Blue (MB) into water bodies has been found to have adverse effects on the environment. Therefore, this study aimed to propose immobilization of a mixed Trichoderma viride and Ralstonia pickettii culture into Sodium alginate–Polyvinyl Alcohol-Bentonite (SA-PVA-Bentonite) matrix as a development method for MB decolorization and degradation. Immobilization process was carried out using the entrapment method, where bacteria and fungi cells were homogenized into the SA-PVA-Bentonite matrix. The results showed that immobilized culture (IMO Mix) outperformed the free cells in Mineral Salt Medium (MSM), achieving an impressive 97.88% decolorization rate for 48 h at 30 °C. Furthermore, a total of 3 metabolite product degradation were produced including Azure A and C, as well as Thionine by LCMS analysis. SEM-EDX analysis confirmed that culture was agglomerated within the SA-PVA-Bentonite matrix, while FTIR demonstrated the functional groups of the synthesized beads. Meanwhile, the difference in charge of bentonite facilitated the adsorption of MB onto the beads, and mixed culture supported the degradation process. This study presented a potential solution to environmental problems, particularly those related to the industrial sector. Further analysis was required to address the challenges associated with other industrial dye waste.

Enhanced Treatment of Basic Red 46 by Ozonation in a Rotating Packed Bed with Liquid Detention

This study investigated the use of ozone in a rotating packed bed (RPB) with liquid detention for the treatment of Basic Red 46 (BR-46). Liquid detention means that liquid accumulates at the lower section to a certain level in the RPB, which leads to longer liquid residence time and greater liquid holdup in the packing and cavity in the RPB. The experimental results showed that the presence of liquid detention in the RPB significantly enhanced the BR-46 treatment effect and ozone absorption rate. With 200 mL of liquid detention in the RPB, the decolorization rate, COD degradation rate, and ozone absorption rate were 34.7%, 62.8%, and 80.0% higher than those without liquid detention. The effects of the rotational speed of the RPB, ozone concentration, initial BR-46 concentration, liquid and gas flow rates on BR-46 degradation were also investigated, and it was found that the high-gravity environment is beneficial to the degradation of BR-46. These results suggest that with the utilization of the liquid detention phenomena in the high-gravity devices, the applications of the high-gravity technology can be extended to the processes where a long liquid residence time is required.