Initial Methylene Blue Concentration Research Articles

NiTiO3 nanoparticles: An environmental game changer in electro-Fenton wastewater remediation

BackgroundIn the face of escalating water pollution challenges, the study explores the efficacy of Electro-Fenton (EF) treatment using NiTiO3 perovskite-modified cathodes for methylene blue (MB) removal from wastewater. MethodsEmploying a Central Composite Design (CCD) methodology, significant factors influencing the EF process, including initial MB concentration, pH, applied current, and reaction time, were optimized. The NiTiO3 catalyst was meticulously characterized, revealing its rhombohedral crystal structure, uniform particle distribution, and efficient charge transfer properties. FindingsElectrochemical analyses demonstrated the superior performance of the NiTiO3/Graphite electrode, emphasizing its increased electroactive sites, enhanced oxygen reduction capability, and reduced charge transfer resistance compared to the bare Graphite electrode. The EF process was finely tuned, demonstrating a 95.38 % removal efficiency of MB at optimal conditions (initial concentration: 25 mg L−1, pH: 4.5, current: 40 mA, time: 110 min). This study underscores the promising potential of NiTiO3-modified cathodes in advanced water treatment applications, highlighting their robust efficiency and environmental significance in combating persistent organic pollutants.

High-efficient removal of methylene blue by zirconium-based organic frameworks modified with 1,3,5-benzenetricarboxylic acid: Characterization, performances, and mechanisms

The vast discharge of methylene blue (MB) dye in industrial effluent, risks the ecological environment, thus making its removal unavoidable. Recently, metal organic frameworks (MOFs) due to their larger pore volume, surface area and easy synthesis have proved to be exceptionally promising materials for contaminant treatment. Based on 1,3,5-benzenetricarboxylic acid (BTC) as a modifier, a new composite material consisting of BTC and Zr-based MOF (UIO-66-BTC) was fabricated for the effective removal of MB from the effluent. Its synthesis and efficient application has been confirmed by characterization analysis. The influencing factors, adsorption isotherms, and adsorption kinetics of MB adsorption by adsorbent were studied. It was demonstrated that the removal rate of MB adsorption by UIO-66-BTC reached 98.45% and the adsorption amount reached 393.80 mg g−1 at temperature (298 K), pH 7, adsorbent dosage (0.5 g L−1), MB initial concentration (200 mg L−1), and contact time of 720 min, respectively. The maximum adsorption of MB by UIO-66-BTC was 20.827 times higher than that of UIO-66 (18.908 mg g−1). The experimental data fits with the pseudo-second-order kinetic model and Langmuir isotherm, implying that the adsorption process is a monolayer chemisorption process. The thermodynamic and regeneration experiments showed that the spontaneous process enhanced the adsorption of MB at lower temperatures and the adsorption efficiency of MB remained above 68% after five successive cycles. The mechanism of MB adsorption on adsorbents is mainly based on electrostatic interactions, pore filling, hydrogen bonding and π-π interactions. It is concluded that this new adsorbent can be effectively used to treat MB in effluents.

Carrageenan/calcium alginate composite hydrogel filtration membranes for efficient cationic dye separation

The development of biopolymer-based filtration systems for water remediation applications is an extremely fascinating area of research. In this paper, we developed a biopolymer-based filtration system using sodium alginate (NaAlg) and carrageenan (Car) for the removal of the toxic cationic dye, methylene blue (MB). The membrane's properties were assessed using FTIR, TGA, UTM, FESEM, EDS, XRD, and water uptake, revealing commendable thermomechanical stability (5.79 MPa), good hydrophilicity, and compatibility. The experimental results further revealed that lambda Car/calcium alginate (λ-Car/CaAlg) exhibited superior dye rejection (100 %) and flux (11.67 L m−2 h−1) compared to kappa Car/CaAlg (κ-Car/CaAlg) (99.22 % and 11.19 L m−2 h−1) and plain alginate (CaAlg) (99.63 % and 9.79 L m−2 h−1). The high MB rejection rate was attributed to the sieving mechanism and electrostatic interaction. A rejection rate of 100 % was achieved at an initial MB concentration of 10 mg/L, pressure of 0.1 MPa, pH of 7, and temperature of 25 °C. Furthermore, the hydrogel membranes demonstrated excellent recyclability over nine cycles, indicating their potential for water treatment applications.

Assessment of chromite ore wastes for methylene blue adsorption: Isotherm, kinetic, thermodynamic studies, ANN, and statistical physics modeling

This research investigates the adsorption potential of chrysotile and lizardite, two minerals derived from chromite ore wastes, for the uptake of Methylene Blue (MB) dye from waste streams. The characterization of these minerals involves XRD, XRF, FTIR, and SEM. Results confirm the dominance of polymorphic magnesium silicate minerals, specifically chrysotile and lizardite, in the samples. The FTIR spectra reveal characteristic vibration bands confirming the presence of these minerals. The SEM analysis depicts irregular surfaces with broken and bent edges, suggesting favorable morphologies for adsorption. N2 adsorption-desorption isotherms indicate mesoporous structures with Type IV pores in both adsorbents. The Central Composite Design approach is employed to optimize MB adsorption conditions, revealing the significance of contact time, adsorbent mass, and initial MB concentration. The proposed models exhibit high significance, with F-values and low p-values indicating the importance of the studied factors. Experimental validation confirms the accuracy of the models, and the optimum conditions for MB adsorption are determined. The influence of solution acidity on MB uptake is investigated, showing a significant enhancement at higher pH values. Isothermal studies indicate Langmuir and Freundlich models as suitable descriptions for MB adsorption onto chrysotile and lizardite. The maximum adsorption capacities of MB for chrysotile and lizardite were found to be 352.97 and 254.85, respectively. Kinetic studies reveal that the pseudo-first-order model best describes the adsorption process. Thermodynamic analysis suggests an exothermic and spontaneous process. Statistical physics models further elucidate the monolayer nature of adsorption. Additionally, an artificial neural network is developed, exhibiting high predictive capability during training and testing stages. The reusability of chrysotile and lizardite is demonstrated through multiple regeneration cycles, maintaining substantial adsorption potential. Therefore, this research provides comprehensive insights into the adsorption characteristics of chrysotile and lizardite, emphasizing their potential as effiective and reusable sorbents for MB uptake from wastewater.

The Using of Plain PAC and PAC Impregnated with MgO and Fe2O3 as Catalysts for the Degradation of Cationic Dyes: Homogenous and Heterogeneous Ozonation

This study presented the removal of methylene blue in the batch system based on catalytic ozonation (heterogeneous and homogenous). The effect of variables such as initial MB (methylene blue)concentration, initial pH of solution (3-11), contact time (5-40 min), and catalyst dosage on homogeneous and heterogeneous ozonation systems was examined. The findings of the research showed that dye removal was better in alkaline conditions. The amount of dye removed in acidic conditions was slightly better than in neutral conditions (approximately 10% to 15%). In addition, the removal efficiency of dye was decreased by increasing of concentration. Besides, as the amount of catalyst (dosage) increased, the removal efficiency of MB had been increased by 40%. Due to the use of catalyst, the significant difference was between the use of two processes of single ozonation processes (SOP) and catalytic ozonation processes (COPs). The results indicated thatMB degradation in COPs was several times faster (approximately 4.7 times). It was due to the numerous advantages of these processes in the removal of environmental pollutants, they can be widely used in the removal of various pollutants if their cost can be reduced.

A Novel Magnetic Nano-Adsorbent Functionalized with Green Tea Extract and Magnesium Oxide to Remove Methylene Blue from Aqueous Solutions: Synthesis, Characterization, and Adsorption Behavior

In this study, a novel green tea/Mg-functionalized magnetic nano-adsorbent, denoted as GTE-MgO-Fe3O4 NPs, was developed and applied to the extraction of Methylene Blue (MB) from water-based solutions. The GTE-MgO-Fe3O4 NPs were synthesized by incorporating green tea extracts (GTE) and Mg species onto the surface of Fe3O4 nanoparticles using a hydrothermal method. Characterization analyses corroborated the successful functionalization of the Fe3O4 surface with GTE and Mg species, resulting in a superparamagnetic adsorbent equipped with abundant surface functional groups, which promoted MB adsorption and facilitated magnetic separation. Batch experiments revealed that different operating parameters had an impact on the adsorption behavior, such as adsorbent dosage, pH, coexisting ions, contact time, the initial MB concentration, and temperature. The investigations of adsorption kinetics and isotherms emphasized that the MB adsorption onto GTE-MgO-Fe3O4 NPs was an exothermic process dominated by chemisorption. The experimental adsorption capacity of GTE-MgO-Fe3O4 NPs for MB surpassed 174.93 mg g−1, markedly superior to the performance of numerous other adsorbents. Ultimately, the utilized GTE-MgO-Fe3O4 NPs could be effectively regenerated through acid pickling, retaining over 76% of its original adsorption capacity after six adsorption–desorption cycles, which suggested that GTE-MgO-Fe3O4 NPs was a suitable adsorbent for eliminating MB from effluent.

The application of magnetite biochar composite derived from parthenium hysterophorus for the adsorption of methylene blue from aqueous solution

The removal of toxic and harmful dyes like methylene blue (MB) from textile wastewater is necessary to reduce environmental pollution. Therefore, this study is aimed at removing MB from an aqueous solution using magnetite-doped biochar of parthenium hysterophorus. Biochar was prepared through pyrolysis techniques at 500 ℃ for 2 h whereas the magnetite and composite material were developed using coprecipitation methods. Herein, NaNO3 and FeSO4. 7H2O were utilized as precursor materials and NaOH as a precipitating agent for preparation of magnetite. Furthermore, pH point of zero charge (pHpzc), Scanning Electron microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) are characterization techniques used to evaluate the nature of the composite material. On the other hand, a full factorial design involving four factors at two levels (24) such as pH (3 and 9), contact time (10 and 40 min), initial dye concentration (100 and 150 mg/L) and adsorbent dosage of 0.01 and 0.04 g/100 mL was used to design and optimize the batch adsorption of MB from an aqueous solution. As a result, a maximum removal efficiency of 99.99% was attained at optimum operating conditions of pH 9, contact time 40 min, initial MB concentration 100 mg/L and adsorbent dosage of 0.04 g/100 mL. Langmuir, Freundlich and Temkin isotherm models were used to investigate the adsorption isotherm in which Freundlich isotherm with a maximum R2 of 0.98 was found to describe the adsorption process inferring multilayer and heterogeneous surface interaction. Additionally, the thermodynamics study depicts that the nature of the adsorption is spontaneous, endothermic and feasible. On the other hand, the chemosorption nature is revealed by the pseudo second kinetics model with a maximum R2 of 0.99. Finally, the remarkable reusability ranging from 99.98% to 97.6% for five consecutive cycles proved that the magnetic biochar derived from parthenium hysterophorus can be used as an effective adsorbent for the decolourization of MB saturated effluent at an industrial scale.

The design and preparation of NDI modified MOFs for high efficiency removal of MB and Cr(VI)

The naphthalene tetracarboxdiimide (NDI) modified NH2-UiO-66(Zr) and NH2-MIL-101(Cr) (NDI/UZr and NDI/MCr for short) metal organic frameworks (MOFs) materials with strong covalent bond OC–N–CO were designed and prepared by solvothermal method. The comprehensive physical and chemical properties of the materials were characterized, and the adsorption and photocatalytic properties of the materials were evaluated by using methylene blue (MB) and Cr(VI) in single and mixture system. When the initial concentration of MB was 50 mg·L−1, the photocatalytic degradation rate constant of NDI/MCr(2:1) was 10.3 and 13.8 times higher than that of NH2-MIL-101(Cr) and NDI/UZr(2:1), respectively. Additionally, NDI/MCr(2:1) exhibited 1.6 times higher reaction rate constant than that of NDI/UZr(2:1) for the removal of 10 mg∙L−1 Cr(VI). The enhanced adsorption and photocatalytic ability over NDI/MOFs were attributed to the MOFs larger specific surface area and wider spectral response, and NDI showed high electron affinity, superior charge carrier transport properties. Free radical and electron capture experiments indicated that h+, •O2−, and e− were the main active species in the NDI/MOFs system. Among them h+ and •O2− played an essential role in the removal of MB, while e− and •O2− contributed to the photocatalytic reduction of Cr(VI). The mechanism of the photocatalytic process was discussed in detail.

Application of Aptenia cordifolia powder as a biosorbent for methylene blue retention from an aqueous medium: Isotherm, kinetic, and thermodynamic investigations

In this study, Aptenia cordifolia powder was utilized as a biosorbent material to effectively treat a synthetic aqueous solution polluted with methylene blue. The characterization of Aptenia cordifolia was conducted according to several analyses, including Fourier transforms infrared, scanning electron microscopy, the point of zero charge and energy dispersive X-ray. The retention process was investigated considering several factors including biosorbent mass, contact time, initial solution pH, temperature, and the initial concentration of methylene blue. The results obtained indicate that the optimal dose of adsorbent was 2 g.L−1. The equilibrium time was approximately 120 min, and the biosorption capacity of the biosorbent increases with an increase in pH. The pseudo-second-order model describes adequately the retention of methylene blue using Aptenia cordifolia. The Langmuir model proved to be more applicable in the analysis of the isotherm data, indicating a maximum retention amount of 51.82 mg.g−1. Moreover, the removal of methylene blue was thermodynamically endothermic, spontaneous, and favorable. These findings demonstrate the potential of Aptenia cordifolia biomass as an effective biosorbent for the treatment of dyes contaminated effluents.

REVIEW OF THERMODYNAMIC AND PHYSICO-CHEMICAL PARAMETERS INFLUENCING METHYLENE BLUE ADSORPTION ON ACTIVATED CHARCOAL OF NATURAL ORIGIN

Methylene blue (MB) is a phenothiazine derivative used in microbiology, surgery, diagnostics and as a sensitizer in the photo-oxidation of organic pollutants. These numerous uses of methylene blue could lead to its accumulation in wastewater, causing harmful effects on the environment and living beings. To combat these harmful effects, numerous wastewater treatment processes, particularly physicochemical, were implemented. Adsorption techniques are particularly used to find new natural, biodegradable and inexpensive adsorbents to treat colored waste from structures such as medical and pharmaceutical laboratories. The aim of the present study was to carry out a relevant bibliographical review of the physico-chemical and thermodynamic parameters that can influence this adsorption of methylene blue on activated carbons of natural origin. The results showed a remarkable elimination of methylene blue. However, parameters such as particle size, adsorbent mass, pH, contact time, initial methylene blue concentration, agitation speed and temperature showed that the adsorption capacity of MB on biosorbents was influenced by these quantities. Similarly, the positive and negative enthalpy values (ΔH°) indicated that adsorption process could be endothermic or exothermic. Other thermodynamic parameters, such as the negative value of Gibbs free energy (ΔG°) and the positive value of entropy (ΔS°), also showed that the adsorption process was feasible and spontaneous.

TiO2-N/Polystyrene photocatalyst-combined Corona Plasma Treatment for Methylene Blue Degradation

<span>This study employed the corona plasma method combined with TiO<sub>2</sub>-N/PS photocatalyst to degrade dye pollutants. The plasma reactor consisted of two needle-shaped stainless steel electrodes connected to a voltage of 8 kV. Methylene blue (MB) solution was used as a model pollutant with varied initial concentrations of 10, 50, and 100 ppm. The degradation efficiency was evaluated based on the absorbance of the degraded MB solution measured using a UV-Vis spectrophotometer. The results exhibited that the longer plasma treatment duration caused the absorbance value of the degraded MB to decrease, and then the MB degradation efficiency increased. MB-10 demonstrated a maximum degradation efficiency of 99.40% after plasma treatment for 30 minutes. Meanwhile, MB-50 and MB-100 reached maximum degradation efficiencies of 95.29 and 86.55% efficiency after plasma treatment for 60 minutes. The greater initial MB concentration caused the longer degradation process. Furthermore, the results revealed no increase in degradation efficiency due to the addition of TiO<sub>2</sub>-N/PS photocatalyst into the plasma treatment. The degradation efficiencies of MB-10, MB-50, and MB-100 under TiO<sub>2</sub>-N/PS-combined plasma treatment for 30 min were 94.48, 81.57, and 5.22%, respectively. This suggests the possibility that the UV light generated during the plasma process cannot activate the TiO<sub>2</sub>-N/PS photocatalyst.</span>

A incorporation of metal into worm-like mesoporous silica materials for selective adsorption of MB in dyestuff

Worm-like mesoporous silica was synthesized using hydroxyethyl cellulose (HEC) as the template agent and sodium metasilicate as the silicon source (hereinafter referred to as HECMS). Different types of metal-doped adsorbents (namely Zr-HECMS-P, Fe-HECMS-P, and Al-HECMS-P) were prepared using the post-grafting method. The three adsorbents were used for the selective adsorption of methylene blue (MB) from an MB/methylene orange (MO) solution. Results showed that under acidic conditions, Fe-HECMS-P exhibited simultaneous adsorption of MB and MO, whereas Zr-HECMS-P and Al-HECMS-P preferably adsorbed MB. Zr-HECMS was determined to be the best adsorbent based on the evaluation results of the selective-adsorption effect of MB in different adsorption environments. Furthermore, different zirconium-silicon molar ratio samples were synthesized (The name is designated as Zr(0.01)-HECMS-P, Zr(0.02)-HECMS-P and Zr(0.04)-HECMS-P.). Results revealed that at pH = 3 and an initial MB concentration of 25 mg/L, Zr(0.01)-HECMS-P exhibited the best selective-adsorption performance for MB, reaching adsorption equilibrium in 2 h with a maximum removal rate of 97.8 %. The adsorption process followed a pseudo-second-order model, and the adsorption mechanism involved coordination and electrostatic action. In a simple binary system (MB + MO), the Zr(0.01)-HECMS-P adsorbent exhibited good selectivity for the MB dye. Finally, after five cycles of regeneration, the adsorption performance of Zr(0.01)-HECMS-P remains stable.

Adsorptive removal of methylene blue dye using durian peel waste reinforced polyvinyl alcohol‐based composite membrane

AbstractA large amount of dye effluents with biodegradable and highly toxic nature from the dyeing and finishing processes has discharged into natural water bodies without adequate treatment, which adversely impacted on aquatic life and human health. Herein, polyvinyl alcohol/agarose/maltodextrin composite membrane (PAM)‐reinforced durian skin fiber is fabricated for methylene blue (MB) uptake from aqueous medium. Structural analyses of the as‐prepared composite membrane are conducted using scanning electron microscopy, Fourier‐transform infrared spectroscopy, water contact angle, and nitrogen adsorption/desorption isotherm measurement. The important influence of experimental conditions including exposure time between adsorbates and adsorbents, initial MB concentration, solution temperature, and pH are also explored. Furthermore, thermodynamic behavior, nonlinear isotherms, and kinetics along with possible adsorption mechanism are provided to attain the insight into the adsorption nature. The results show that PAM‐reinforced durian peel waste possesses high MB adsorption capacity (105.54 mg g−1), which was controlled by diffusion and chemisorption mechanism. The thermodynamics of methyl blue removal on the composite membrane suggest that the adsorption is spontaneous, favorable, and endothermic in nature. This contribution is expected to inspire the efficient utilization of agriculture by‐products into eco‐friendly and biodegradable adsorbents to purify the dye‐contaminated water.

Chitosan coated biomass waste-based magnetic hydrogel beads for the removal of methylene blue

Due to developing technology and increasing population, human needs have increased, and textile activities have gained momentum. Many synthetic dyestuffs are used to meet the needs in this field. In this study, a cheap, useful, innovative, environmentally friendly and sustainable adsorbent was developed for the removal of Methylene Blue(MB), which is one of the dyes that is harmful to the environment. In the cultivation of fruit trees, in addition to the product, very high amounts of by-products/waste (garbage, branches, bark, leaves, etc.) are produced. In this direction, fig tree wastes were immobilized with chitosan, made magnetic, and MB adsorption on the developed adsorbent was examined in a batch system. Glutaraldehyde was used as crosslinker. Characterization of synthesized glutaraldehyde cross-linked chitosan-coated magnetic vegetable waste composite beads (g-CMBW) was carried out by SEM, EDX, FTIR and XRD. In the study, the effects of temperature (25–55 °C), pH (3.0–8.0), initial MB concentration (10–250mg/L), contact time (5–360min) and the amount of adsorbent (2–10 g/L) on MB adsorption with g-CMBW were examined. The optimum conditions obtained were determined as pH 6.0, temperature 25 °C, adsorbent amount 6 g/L, and contact time 120 min. The maximum adsorption capacity in MB removal using g-CMBW composite beads was calculated as 103.1 mg/g according to the Langmuir isotherm model. The temperature studies showed that the adsorption capacity decreased with increasing temperature, showing that the system was exothermic. In light of these results, it was determined that there are new promising adsorbents of natural origin, with higher adsorption capacity, lower cost, and alternatives to commercially used adsorbents in the removal of MB from aqueous media.

Exploring a new vanadophosphate Li(C4N2H12)2[(HPO4)(VO)3(PO4)3]: Synthesis, Characterization, and catalytic behavior

Li(C4N2H12)2[(HPO4)(VO)3(PO4)3], a new vanadophosphate (VPO) material we synthesized using a hydrothermal route, crystallizes in the orthorhombic system (S.G.: Pna21), with the cell parameters: a = 14.6207(7) Å, b = 8.7090(3) Å, c = 17.6208(7) Å, V = 2243.69(16) (Å3), Z = 4. The crystal structure consists of bc-parallel layers of alternating polyhedra VO5, VO6 combined with PO4 or HPO4 tetrahedra. The layers stack provides cavities hosting Li+ cations. Within the interlayer space, protonated organic molecules act as a template and create hydrogen bonding interactions with the inorganic network. To assess its properties, the hybrid material’s thermal stability and reactivity were investigated using the IR spectroscopy and thermal analysis (TG/DTA). The potential of the title compound was investigated on the adsorptive removal of methylene blue (MB) dye by studying various parameters like pH, temperature, initial dye concentrations and contact time. The kinetic study revealed a gradual process of the dyés adsorption, with a removal efficiency of 99 % for initial MB concentrations of 50 ppm at pH = 7. The degradation MB continues even after three hours of oxidative reaction.

Design of Experiments for Increasing of Methylene Blue Adsorption onto Cellulose Derivative-Based Composites

Hematite-cellulose acetate composite membranes (M1, M2, and M3) were evaluated for their performance in methylene blue (MB) adsorption. Box-Behnken design was used to evaluate the influence of operational parameters on the adsorption of MB by these adsorbents. The idea was to optimize the process with maximum efficiency on adsorption, through identification of the influential factors to the process, evaluation of interactions between these factors, and modeling mathematical expressions. Adsorption experiments versus time were better described by the non-linear pseudo-first-order model, followed by the pseudo-second-order model, and then the non-linear pseudo-first-order model. The R2 and chi-square values corroborate this finding. Equilibrium data was also evaluated and modeled to the linear and non-linear Langmuir and Freundlich isotherm models. The linear isotherm models were better models to fit the adsorption equilibrium data on the membranes, followed by the non-linear Langmuir model. Thus, it was presumed that chemisorption was the prevailing adsorption mechanism. Additionally, adsorption proved to be exothermic and spontaneous. A quadratic model equation was found to describe the interaction between factors. The coefficients of pH and MB concentration were positive, thus positively affecting the adsorption of MB, but those of the temperature were negative, justifying the negative effect on the adsorption process. Analysis of variance (ANOVA) showed a high coefficient of determination value and a high prediction of the regression model was derived. The highest adsorption capacity was found at the optimum experimental conditions of pH = 9.0, MB initial concentration = 100 mg · L-1 and temperature = 20 ℃. Finally, the composites provided 5 use cycles which is good when considering the adsorbents used in removing textile dyes from wastewater.

Photocatalytic Degradation of Methylene Blue Dye by Promising Zinc Copper Ferrite Nanoparticles for Wastewater Treatment

AbstractIn this work, crystalline copper-zinc ferrite nanoparticles were synthesized by a simple co-precipitation method. Morphological characterization of produced samples was done using a scanning electron microscope (SEM). A transmission electron microscope (TEM) was utilised for further identification and confirmation of the particle morphology and size. Moreover, Fourier transformation infrared (FTIR) spectroscopy and X-ray diffraction (XRD) was employed to examine crystalline structure, chemical structure, and surface area respectively. Optical properties were examined by UV–Vis spectroscopy. The results indicate that the Zn0.5Cu0.5Fe2O4 nanoparticles’ crystallite size was 28.5 nm. The experiments focused on the impact of various factors, such as pH levels, initial MB concentration, and nanocatalyst dosage, on the observed photocatalytic efficiency. The photocatalytic performance of Zn0.5Cu0.5Fe2O4 nanoparticles under UV light was evaluated by decolorization of Methylene Blue (MB) azo dye. Photocatalysis degradation of 10 ppm of MB adding 15 mg of Zn0.5Cu0.5Fe2O4 nanoparticles was 94% after 135 min at room temperature and pH value of 9. Further interpretation was carried out and a proposed mechanism for the MB photodegradation by Zn0.5Cu0.5Fe2O4 nanoparticles was suggested.

Simultaneous removal of methylene blue dye and waterborne pathogens from wastewater using extract of Embelia schimperi fruits

In this study, we report the use of Embelia schimperi fruits’extract to simultaneously remove methylene blue dye and pathogens from wastewater. The extract of Embelia schimperi fruits was characterized by Atomic force Microscopy and Fourier Transform Infra-Red spectroscopy. The adsorption properties of the crude extracts of the fruits were explored as a function of dosage, contact time, pH, initial methylene blue concentrations, and temperature. As a result, the highest removal efficiency of methylene blue was found to be 99.2% at optimum conditions. The adsorption data demonstrated that the adsorption of Embelia schimperi followed the Langmuir isotherm model (R2 = 0.94899) and the pseudo-second-order kinetic model (R2 = 0.99326). Besides, crude extracts of the fruits showed significant antibacterial properties against gram-positive and gram-negative bacteria. Agar diffusion tests confirmed that Listeria monocytogenes and Staphylococcus aureus were highly sensitive to the crude extracts of Embelia schimperi fruits, followed by Escherichia coli and Salmonella typhi. Thus, the findings of this study confirm the promising potential of Embelia schimperi fruits as a natural adsorbent used to remove methylene blue dye and pathogenic bacteria at the same time from wastewater.
 KEY WORDS: Embelia schimperi, Adsorption, Isotherm, Kinetic, Methylene blue, Waterborne pathogens
 
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 281-296. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.1 

Photocatalytic Epoxy Paint Based on TiO2 for the Decontamination of Water under Visible LED and Sunlight Irradiation

AbstractSemiconductor oxides such as titanium dioxide (TiO2) have been used as photocatalysts for removing contaminants. In addition, TiO2 nanoparticles in suspension form are difficult to recover and recycle, and they are expensive. In our work, titanium dioxide has been immobilized on a commercially available, thermally stable, chemically stable, and cheap polymer. The nanocomposite is synthesized with varying percentages of TiO2, 0.25, 0.5, and 1 weight percent. The obtained nanocomposites were characterized, and the effect of the process parameter (i. e., initial concentration of MB, amount of catalyst, light wavelength, and power of light) was investigated. Also, the results show good photodegradation of MB by the TiO2‐epoxy nanocomposite. The decomposition of 10 ppm methylene blue (MB) during 200 min under 25 W visible LED irradiation can reach 95 %. This value is higher than that obtained with pristine TiO2, which does not have photocatalytic activity under LED light. The antibacterial activity of nanocomposites concerning Escherichia coli and Stephalocous aureus was studied, and an inhibition zone of 2 cm and 3.5 cm was obtained, respectively. Therefore, the TiO2‐epoxy nanocomposite was applied to a glass jar and tested after four months for the degradation of methylene blue (5 ppm) and methyl orange (8 ppm) under sunlight. The paint demonstrated good photocatalytic efficiency of 41 % and 72 % within 310 min, respectively.

Tailoring structural, optical, and magnetic properties of Y3+ doped CoFe2O4 nanoparticles to enhance photocatalytic activity

In recent times, there has been a significant focus on semiconductive magnetic nanomaterials due to their potential in photocatalytic applications, primarily because of their easy recoverability. In this work, CoYxFe2-xO4 nanoparticles (with varying x values: 0, 0.05, 0.10, 0.15, and 0.20) were successfully synthesized. The incorporation of Y3+ ions induced notable transformations in the structural, optical, microstructural, magnetic, and photocatalytic properties of CoFe2O4 nanoparticles. Analytical techniques such as x-ray diffraction, fourier transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, photoluminescence, transmission electron microscopy, vibrating sample magnetometry, and electron paramagnetic resonance spectroscopy were employed to investigate these effects. The investigation into the photocatalytic degradation of methylene blue (MB) under ultraviolet light irradiation was carried out. The influence of distinct elemental compositions, catalyst quantities, irradiation durations, and initial methylene blue concentrations on the decolorization process was assessed.