Rhodamine B Research Articles

Development of a novel lightweight brick-activated carbon based BiVO4 photocatalyst and its adsorption-photocatalytic behavior for toxic dye removal in wastewater

The purpose of this research was to develop a novel photocatalyst by loading BiVO4 (BVO) particles on lightweight brick-activated carbon (LWB-AC). The characterizations of as-prepare samples were studied using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–VIS –NIR spectrophotometer (UV-VIS-NIR) techniques. The adsorption-photocatalytic methylene blue (MB) removal, methyl orange (MO) removal and rhodamine B (RhB) removal of the as-prepared LWB-AC based BVO photocatalyst were tested by irradiating visible light. The results showed that the LWB-AC based BVO photocatalyst exhibited the highest adsorption-photocatalytic efficiency for the removal of MB, MO and RhB dyes under visible light irradiation as compared to the other samples. This might be due to the synergistic effect between AC and BVO on the surface of LWB. Moreover, the presence of both AC and BVO on the surface of LWB helped in preventing the electron-hole recombination, resulting in the enhanced adsorption-photocatalytic activity. For reusability tests, the LWB-AC based BVO photocatalyst did not show the loss of adsorption-photodegradation ability of MB, MO and RhB dyes after five runs. A probable adsorption-photodegradation mechanism of LWB-AC based BVO photocatalyst was also proposed.

The preparation and characterization of WS2 nanomaterials with different morphologies and the mechanistic study of peroxymonosulfate activation for phenol degradation

Transitional metal chalcogenides like WS2 play a significant role as cocatalysts in activating PMS (peroxymonosulfate) due to their high reductivity. Three WS2 samples with different morphologies, specific surface areas, and 1 T phase contents were prepared in this study. Characterizations by SEM, TEM, BET, XRD, Raman, XPS, and catalytic degradation experiments confirmed that the a-WS2 sample exhibited the richest morphology, the largest specific surface area, the highest 1 T phase content, and the best cocatalytic performance. The a-WS2/Fe(II)/PMS system efficiently degraded 20 mg/L phenol within 15 minutes and was also effective in degrading pollutants like RhB (Rhodamine B) and OFX (Ofloxacin). Characterization predicted the degradation pathway of phenol and revealed 10 intermediate products. The degradation mechanism indicated that the presence of WS2 accelerated the conversion of Fe(III) to Fe(II), thereby further promoting the activation of PMS. ·SO4−, ·OH, and ·O2− were identified as the main active radicals in this system. a-WS2 exhibits characteristics such as high catalytic performance, good stability, high recyclability, and a low ion leaching rate, and it generates sulfur vacancies during use. This system shows promising prospects in the treatment of high-concentration organic wastewater.

Synthesis of MoS2@MoO3/(Cu+/g-C3N4) ternary composites with double S-scheme heterojunction for peroxymonosulfate activation exposing to visible light

The construction of semiconductor heterojunction is an effective way for charge separation in photocatalytic degradation of pollutants. In this study, a novel MoS2@MoO3/(Cu+/g-C3N4) ternary composites (MMCCN) was prepared via a simple calcination method. The as-prepared composites exhibited exceptional performance in activating peroxymonosulfate (PMS) for the degradation of rhodamine B (RhB). The activity testing results indicated that 99.41 % of RhB (10 mg·L−1, 10 mL) was effectively removed by the synergistic effect of composites photocatalyst (0.1 g·L−1) and PMS (0.1 g·L−1) under visible light irradiation for 40 min. Its reaction rate constant exceeded that of Cu+/g-C3N4, MoO3 and MoS2 by a factor of 3.56, 17.30 and 11.73 times, respectively. The crystal structure, band gap and density of states (DOS) of the semiconductors were calculated according to the density functional theory (DFT). Free radical trapping tests and electron spin resonance spectroscopy validated that 1O2, O2− and h+ are primary reactive species participating in the decomposition of RhB. The ternary composites demonstrated good stability and maintained excellent degradation efficiency even across four reaction cycles. Furthermore, the activation mechanism and the intermediates produced during the decomposition course of RhB by MMCCN/PMS/vis system were analyzed and elucidated. A double S-scheme heterojunctions was responsible for efficient separation of photo-induced electron-hole pairs. This work presents a novel method in the construction of double S-scheme heterojunctions for PMS activation which is expected to find wide applications in wastewater treatment and environmental remediation.

Fabrication of a novel microflower BiOCl composite incorporated with rosemary powder for enhanced oxygen vacancies and visible-light photocatalytic efficiency

Incorporating metallic or nonmetallic compounds is a promising method for enhancing the oxygen vacancies (OVs), charge transport, and visible light absorption of a bismuth oxychloride (BiOCl) semiconductor. This research aims to improve the properties of BiOCl by incorporating rosemary powder (RPC). BiOCl photocatalysts with enhanced OVs were synthesized through the addition of 1–4 wt% of RPC using a one-pot solvothermal process. The addition of 3 % RPC resulted in the formation of very small particles on the BiOCl lamellar structures, which were aligned with the (002) plane of carbon quantum dots (CQDs). The uniformly distributed CQDs transformed the BiOCl microstructure from a two-dimensional lamellar structure to a three-dimensional floral structure, leading to an increased surface area and pore volume. The incorporation of RPC enhanced the visible light absorption capacity of BiOCl. The carbon atoms in RPC readily attach to oxygen atoms in the Bi-O bond, disrupting the Bi-O lattice bond and forming OVs. The addition of RPC contributed to a higher number of OVs, which impacted both the energy difference between the valence and conduction bands and their locations. This resulted in better charge transfer and enhanced active species formation. The 3 %-RPC-BOC photocatalyst had the highest efficiency, achieving a 98 % degradation of rhodamine B (RhB) and a 45 % removal of organic carbon within 48 min under visible light. This composite also had excellent stability and reusability, as its crystal structure remained unaltered even after conducting 7 cycles. The primary active species of 3 %-RPC-BOC system is the superoxide radical (·O2-), while the hydroxyl radical (·OH) and hole (h+) operate as minor active species. Additionally, the 3 %-RPC-BOC achieved a high tetracycline (TC) removal rate of 82.1 %, which is 2.21 times higher than that of pure BiOCl.

One-Step Self-Assembled WO3/rGO Microspheres Photoanode Assembled Efficient Photocatalytic Fuel Cells for Simultaneous Organic Pollutant Degradation and Electricity Generation.

Photocatalytic fuel cells (PFCs) present a promising and environmentally friendly approach to simultaneously treat organic pollutants in wastewater and electricity generation. The development of photoanodes with high light absorption and carrier mobility is essential for enhancing the performance of PFCs but remains challenging. Herein, a one-step self-assembly strategy was adopted to develop flower-like WO3/rGO microspheres for PFC devices. Attributed to the abundant surface-active sites, enhanced light harvesting, and efficient separation of photogenerated charge carriers, the WO3/rGO photoanode demonstrated superior rhodamine B (RhB) degradation rate (90% in 2 h), maximum power density (4.74 μW/cm2), and maximum photocurrent density (0.096 mA/cm2), 1.4, 2.4, and 4.0 times higher than the corresponding pure WO3 photoanode, respectively. Density functional theory (DFT) calculations reveal that the built-in electric field formed between the interface of WO3 and rGO promotes the transfer of photogenerated electrons from WO3 to rGO, thus exerting a significant impact on improving the migration and separation of photoinduced charge carriers. Moreover, by combining experimental and theoretical results, a complete PFC operation mechanism for the PFC system was proposed. This study focuses on the strategy of constructing rGO-doped photocatalysts to enhance the interfacial charge transfer mechanism, providing a promising approach for the development of high-performance photoanodes in PFC systems.

In-situ constructing oxygen-enriched vacancies BiOCl with 3D flower-structure for exceptional visible-light-driven photocatalytic properties

Bismuth oxychloride (BiOCl), emerging as a novel environmentally friendly nanomaterial, possesses considerable potential for photocatalytic degradation of organic wastewater. However, inadequate active sites and inhibited electron separation efficiency severely hinder its visible-light photocatalytic activity. To address this issue, herein we present a facile approach to in-situ construct BiOCl three-dimensional (3D) flower-structure (BOC-F) with oxygen-enriched vacancies for abundant active sites and effective electron separation efficiency through morphology control and vacancy engineering. The visible photocatalytic activity of BOC-F and BiOCl with 2D flaky-structure (BOC-S) was assessed through a systematic examination of the degradation efficiencies of tetracycline hydrochloride (TC-HCl) and rhodamine B (RhB). Under visible light irradiation, BOC-F exhibited superior visible photocatalytic activity, effectively degrading tetracycline hydrochloride (TC-HCl) (20 mg/L) and rhodamine B (RhB) (200 mg/L) within 90 min and 20 min of light exposure, respectively. The findings elucidate that BOC-F, possessing a 3D flower structure, manifests a heightened concentration of oxygen vacancies in contrast to BOC-S, consequently yielding excellent performance. Moreover, The ESR test showed that singlet oxygen (1O2) and hole (h+) were two main active species in the photocatalytic degradation of BOC-F. This work not only furnishes a facile method for constructing oxygen-rich vacancies in BiOCl but also provides fresh insights into the potential for enhancing the visible photocatalytic properties of Bi-based materials through vacancy engineering.

Fabrication of charged and zwitterionic nanofiltration membranes and anti-adhesion analysis using quartz crystal microbalance with dissipation and atomic force microscopy

Three nanofiltration (NF) membranes (positive charge, negative charge and near charge neutrality) were fabricated to investigate the anti-adhesion mechanism. Among them, the NF membrane with positive charge was synthesized through an electrophilic substitution reaction between the amino group of polyethyleneimine (PEI) and the chloromethyl groups of chloromethyl polysulfone (CMPSf) on a supporting polysulfone (PSf)/CMPSf blend membrane. The NF membrane with negative charge was fabricated through polycondensation using 1, 3, 5-benzenetricarbonyl trichloride (TMC) as a reactive monomer on the positive charge NF membrane. Subsequently, the near charge neutral zwitterion NF membrane (ZNF) was prepared by grafting 3-((2-aminoethyl) dimethylammonio) propane-1-sulfonate (sulfobetaine) (ADSS) onto the negative charge NF membrane. The anti-adhesion behaviors of the NF membranes during the dye selective separation were analyzed by Atomic force microscopy (AFM) and quartz crystal microbalance with dissipation (QCM-D). The results demonstrated that the near charge neutral ZNF membrane displayed a higher dyes rejection (>94.4 %) and higher flux recovery rates (>88.1 %) than charged NF membranes. Meanwhile, the near charge neutral ZNF membrane demonstrated the lowest amounts of dye deposition compared with charged NF membranes, such as reactive blue 4 (R4) for 509.9 ng/cm2, basic blue 24 (BB 24) for 269.0 ng/cm2, rhodamine B (RB) for 197.4 ng/cm2). Additionally, the near charge neutral ZNF membrane with the thicker hydration layer (121.7 nm) displayed weaker interaction forces (−4.8 nN to −7.4 nN) with the dyes than the charged membranes (−10.4 nN to −28.6 nN). Finally, an anti-adhesion mechanism involved charged shielding effect and hydration layer formation was proposed. These observations provide comprehensive insights into the anti-adhesion mechanism of ZNF membrane.

Bacterial Cellulose Incorporating Multicolor Fluorescent Probes for Visual Acidity Detection in Paper-Based Cultural Relics.

Paper-based cultural relics often undergo acidification and deterioration during long-term preservation. Accurate detection of paper acidity is of great significance to assess aging status and extend the preservation lifetime of paper-based cultural relics. Rapid identification of the acidification degree and acid distribution across multiple regions of paper is essential. Inspired by fluorescent sensing technology, pH-sensitive cadmium telluride (CdTe) quantum dots (QDs) and rhodamine B (RB) fluorescent probes are synthesized and incorporated onto the nanofibers of a bacterial cellulose (BC) membrane to enable visual acidity detection of paper. Due to the complementary pH detection range of CdTe QDs and RB probes, the composite BC membrane exhibits a clear pH response across an acidic to neutral range (pH 3.0-7.5). Notably, the contrasting fluorescent colors of the two probes within the BC membrane allow for easy visualization of paper pH and acidity distribution with the naked eyes. A distinct color transition from red to green was observed on the fluorescent BC membrane when it is applied to a model paper with a gradient pH distribution. The feasibility of this method was verified by using the flat-headed pH electrode method. Additionally, common metal ions in most paper fillers, inks, pigments, as well as some sugars and amino acids showed minimal interference with the pH response of the composite BC membrane, highlighting its potential and broad applicability for visual acidity detection in paper-based cultural relics.

Coconut Shell Carbon Preparation for Rhodamine B Adsorption and Mechanism Study.

Phosphoric acid is used as a chemical activator to prepare coconut shell carbon (PCSC), and for investigating rhodamine B (RhB) adsorption performance. The optimal conditions for the preparation of PCSC (calcined temperature, phosphoric acid concentration), and the influence of adsorption conditions (concentration, pH, etc.) on RhB and the recovery performance of optimal carbon are investigated. Experimental results show that when the amount of PCSC (600 °C, 2 h) is 0.2 g, the initial RhB concentration is 10 mg/L, pH = 6, and the adsorption time is 30 min, it can have 95.84% RhB adsorption efficiency. Liquid ultraviolet spectroscopy also supports this adsorption performance. Characterization data showed that hydroxyl and ester groups, aromatic structures, and PO43- existed on the surface of PCSC, and the amount decreased with increasing calcined temperature. PCSC has a BET (N2) surface area of 408.59 m2/g and has a micropore distribution, EDS-detected P content is 3.91%. SEM showed that the PCSC formed micropores which could better adsorb RhB. The kinetic and thermodynamic analysis of the adsorption of RhB by PCSC showed that the adsorption process was in accord with quasi-secondary kinetic equations and ΔGθ was between -1.65 and -18.75 kJ/mol. The adsorption was a physical adsorption and a spontaneous endothermic reaction, and the obtained PCSC sorption isotherms were classified as Langmuir-type. The RhB adsorption mechanism on PCSC includes pore diffusion, hydrogen bonding, and π-π conjugation. The PCSC prepared by H3PO4 modification has superior adsorption and recycling performance for RhB, providing a reference for the preparation of other biomass carbon materials for the treatment of dye wastewater.

Investigation of the efficacy of graphite-sulfur iron tailing composite catalysts for activation of peroxydisulfate for rhodamine B degradation.

Herein, a novel graphite/sulfur iron tailing composite was applied as a peroxydisulfate (PDS) activator for rhodamine B (RhB) degradation in the water. The superior catalytic efficiency of graphite/sulfur iron tailing was achieved through radical (SO4•- and •OH) and non-radical (1O2) processes according to the radical quenching experiments and electron paramagnetic resonance analysis. The carbonyl group and Fe species were the main active sites on the surface of graphite/sulfur iron tailing, which was demonstrated by combining Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and reaction kinetic experiments, and a possible degradation mechanism was also proposed. Overall, activated with 0.30g/L of C-1, PDS achieved a 94.8% removal rate for RhB and maintained a removal rate of over 85% even after five consecutive operation cycles, and this study will benefit the application of iron/carbon composite materials in practical water treatment.

Effective hydrogen production and coupling degradation of organics (4-nitrophenol, methylene blue, and Rhodamine B) in wastewater by electrospun PAN@Fe0 composite nanofibers

The pursuit of clean energy generation and environmental preservation is of utmost importance for societal progress. However, couple clean energy production and pollution control is still a difficulty. In this study, a novel electrospun composite mat, with nano zero valent iron (Fe0, nZVI) encapsulated into polyacrylonitrile (PAN) nanofibers was acted as a catalyst. The activation energy (Ea) for the hydrolysis of NaBH4 to produce hydrogen is 22 kJ·mol−1, hydrogen atom utilization efficiency (HGE) of NaBH4 is 60.80%. Three kinds of organic dyes 4-nitrophenol (4-NP), methylene blue (MB), and Rhodamine B (RhB) were served as the model pollutant, to construct NaBH4-organic system for energy production and pollution reduction. The NaBH4-organic system demonstrates a collaborative capability to simultaneously remove organic pollutants and generate hydrogen, with a coupling equilibrium point between the two processes. The hydrogen generation rate (HGR) and HGE increased with the concentration of pollutants increased. The degradation of 4-NP, MB, and RhB followed pseudo-first-order kinetics, with RhB degrading dosage 20 and 44 times higher than 4-NP and MB, respectively. H2 and H· contributed to the organic degradation. nZVI directly participated in the formation H2 and H·. PAN@Fe0 possessed good recyclability and moderate cost. The degradation process adhered to the classical surface reaction controlled Langmuir-Hinshelwood (L-H) model. The integration of synergistic production capacity and pollutant degradation aligns well with the principles of green chemistry and sustainable development. This study demonstrates a novel approach to no precursor loss catalysts preparation, efficient production clean H2, advanced treatment of dye-containing wastewater, carbon neutral operation of sewage treatment plant.

Preparation of ZIF-67 derived Co3O4 composite non-homogeneous catalysts with cerium oxide for the efficient degradation of Rhodamine B

The textile printing and dyeing industry produces a significant amount of wastewater, which is challenging to degrade due to its high organic concentration, complex composition, and high chromaticity. This type of wastewater is considered one of the most difficult to treat. In recent years, advanced catalytic oxidation based on sulfate radicals (SO4−) can efficiently degrade printing and dyeing wastewater. Seeking non-homogeneous catalysts for the activation of the radicals is the key problem to be solved nowadays. In this study, Ce/Co-ZIF precursor was obtained by stirring and precipitation, and the ZIF-67-derived non-homogeneous catalyst of Co3O4 and CeO2 was successfully synthesised by calcination for the efficient catalytic degradation of Rhodamine B (RhB) dye. The morphological structure and elemental distribution of the non-homogeneous catalysts were observed using SEM, TEM, XRD, and XPS. Additionally, the factors that affect the degradation of RhB dye were investigated. These factors were adjusted individually, from CeO₂ loading, pH, material dosing, to persulfate (PS) dosing, and it was determined that the rate of RhB degradation also increased from the initial 92 % to a value of 97.1 %. It was found that under the optimal conditions of a CeO2 loading percentage of 0.44, pH of 7, and composite material and potassium persulfate dosage of 5 mg and 0.4 g/L, respectively, the catalytic system achieved a degradation rate of 97.5 % of RhB dye within 30 min. Then the non-homogeneous catalyst could still maintain the good catalytic degradation effect after 5 cycles of regeneration experiments. Therefore, the ZIF-Co3O4@CeO2 non-homogeneous catalyst has a good potential for wastewater treatment and provides a new way for the application of high performance catalysts in the future.

La3+-Schiff base complex for the degradation of Rhodamine B: Kinetic studies and reactive species identification

The research investigates the characteristics of the La-H2L complex through molar conductivity experiments, XPS, SEM, EDX, BET and UV-visible spectroscopy, revealing a band gap of 2.76 eV. Its photocatalytic efficacy was tested for the degradation of Rhodamine B (RhB) dye under UV light. Optimization studies determined the optimal conditions for pH, initial dye concentration, and catalyst dosage, leading to a 72.2 % reduction in RhB concentration. Kinetic analysis demonstrated that the degradation followed pseudo-first-order kinetics with a rate constant of 0.0169 min⁻¹. Scavenger studies identified hydroxyl radicals, holes, and superoxide radicals as the primary reactive species involved. High-Resolution Mass Spectrometry (HRMS) identified intermediate products and provided insights into the degradation pathways. The La-H2L complex exhibited remarkable stability and reusability, retaining 85 % of its photocatalytic activity after five cycles. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) confirmed the structural integrity and stability of the complex post-degradation. These results underscore the La-H2L complex's potential as a highly effective and durable photocatalyst for environmental remediation.

Hydrothermal synthesis of BCQD@g-C3N4 nanocomposites supporting environmental sustainability: Organic dye removal and bacterial inactivation

Various studies are being carried out on the removal of organic dyes and the production of antibacterial agents. In this study, boron-doped carbon quantum dot (BCQD) was synthesized by hydrothermal method, and BCQD@g-C3N4 nanocomposite structure was synthesized using graphitic carbon nitride (g-C3N4) as the support material. The photocatalytic activity of the synthesized nanocomposite against MO, RhB dyes, and Escherichia coli (E. coli) bacteria was investigated. The surface, morphology, molecular, and crystal properties of BCQD@g-C3N4 were investigated using characterization methods such as Transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Fluorescence (FL) spectrophotometer, and X-ray diffraction (XRD). As a result of TEM analysis, it was determined that the average particle size of BCQD was 5.1 ± 1.14 nm and showed a homogeneous distribution on 2D g-C3N4. In the XRD spectrum for BCQDs, the diffraction peak corresponding to the (002) amorphous carbon phase was observed at 21.65° In the PL spectrum of B-CQD@g-C3N4s, the emission value was observed at 458 nm. In the study conducted by taking advantage of the photocatalytic feature of BCQD@g-C3N4 nanocomposite, Rhodamine B (RhB) and Methyl orange (MO) were degraded by 65.58 % and 73.56 %, respectively, at the end of 120 min. Additionally, BCQD@g-C3N4 photocatalyst completely inhibited the growth of E. coli bacteria, which are frequently encountered in wastewater, at 90 minutes under sunlight. Escherichia coli (E. coli), which is frequently encountered in wastewater, BCQD@g-C3N4 completely prevented bacterial growth in the 90th minute under sunlight.

Application of ANN and RSM for Rhodamine B and Safranine-O Decolorization on Zinc-Carbon Battery Waste Derived Ag/CoFe-LDH/rGO Catalyst.

The present work is first aimed at recovering graphite from carbon rods of waste zinc-carbon (Zn-C) batteries for applications such as wastewater treatment, in order to contribute to the development of a sustainable environment. Then, a composite material, cobalt-iron layered double hydroxide combination with reduced graphene oxide, and with subsequent Ag nanoparticles deposition via NaBH4 reduction method (Ag/CoFe-LDH/rGO) was prepared for the catalytic activity of Rhodamine B (RhB) and Safranine-O (SO) as model contaminants from aquatic media. The catalytic activity of RhB and SO by Ag/CoFe-LDH/rGO in the presence of NaBH4 was studied to model and optimize the process parameters (NaBH4 amount, reaction time, initial dye concentration (Co), and catalyst dosage) via central composite design (CCD)-response surface methodology (RSM). Also, an artificial neural network (ANN) model was developed to estimate the catalytic activity of each dye using an RSM data set. The catalytic activities of 99.54% and 99.96% were obtained for RhB and SO dyes, respectively, under the optimal conditions: NaBH4 amount 12.32 mM, reaction time 3.19 min, Co 33.46 mg/L, and catalyst dosage 1.24 mg/mL for RhB dye; NaBH4 amount 16.76 mM, reaction time 3.06 min, Co 15.10 mg/L, and catalyst dosage 1.46 mg/mL for SO dye. The optimum conditions of process parameters by ANN with gray wolf optimizer (GWO) were in good agreement with the points determined the RSM-CCD. These results demonstrate that RSM and ANN approaches can be applied practically and efficiently to maximize the catalytic activity of RhB and SO by Ag/CoFe-LDH/rGO in the existence of NaBH4. On the other hand, from the kinetic and thermodynamic studies, the positive activation enthalpy, ΔH# and the negative activation entropy, ΔS# values for each dye demonstrated that the catalytic performance was endothermic and less random at the solid/liquid interface.

Integrating machine learning with experimental investigation for optimizing photocatalytic degradation of Rhodamine B using neodymium-doped titanium dioxide: a comprehensive approach with toxicity assessment.

In this study, neodymium-doped titanium dioxide (Nd-TiO2) nanoparticles were synthesized via a hydrothermal method for the photocatalytic degradation of Rhodamine B (RhB) under UV and sunlight conditions. The properties of these NPs were comprehensively characterized. And optimization of RhB degradation was conducted using control-variable experiment and artificial neural networks (ANN) under various operational conditions and in the presence of competing compounds. The acute toxicity of both NPs, RhB, and the environmental impact of the photocatalytic treatment effluent on Danio rerio were evaluated. The Nd modification increased the catalyst's specific surface area and thermal stability. X-ray diffraction confirmed the tetragonal anatase phase in undoped TiO2, while Nd-doped TiO2 exhibited shifts in peaks and the presence of brookite and rutile phases. Nd (1mol%) doped TiO2 demonstrated superior RhB photocatalytic degradation efficiency, achieving 95% degradation and 82% total organic carbon (TOC) removal within 60min under UV irradiation. Optimization under sunlight conditions yielded 95.14% RhB removal with 0.28g/L photocatalyst and 1% doping. Under UV light, 98.12% RhB removal was optimized with 0.97% doping, along with the presence of humic acid and CaCl2. ANN modeling achieved high precision (R2 of 0.99) in modeling environmental photocatalysis. Toxicity assessments indicated that the 96-h LC50 values were 681.59mg L-1 for both NPs, and 23.02mg L-1 for RhB. The treated dye solution exhibited a significant decline in toxicity, emphasizing the potential of 1% Nd-TiO2 in wastewater treatment.

Hyper-Cross-Linked Polyindole for Selective Adsorption and Resource Utilization of Organic Pollutants in Water.

Efficient treatment and utilization of organic pollutants in water are difficult for environmental remediation. A new hyper-cross-linked polymer (PIn-HCP) with high specific surface area was constructed via polyindole (PIn) as building blocks. Rich pore structures and abundant adsorption sites in PIn-HCP were obtained by hyper-cross-linking. The specific surface area of PIn-HCP was enhanced from 14.85 to 431.89 m2/g. The adsorption capacities of PIn-HCP-2 for methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and tetracycline hydrochloride (TH) are 902.0, 275.2, 16.0, and 0.0 mg/g, respectively. PIn-HCP also realized selective adsorption of MB, which can better separate MB/RhB and MB/TH. MB is adsorbed onto PIn-HCP via a synergistic mechanism including π-π stacking, electrostatic interaction, cation-π interaction, hydrogen bonding interaction, and ion exchange. The huge conjugated structure of PIn promotes PIn-HCP to selectively adsorb MB. In addition, PIn-HCP also retains the electrochemical properties of PIn. MB can improve the specific capacitance of PIn-HCP up to five times, and it has potential as a supercapacitor electrode. PIn-HCP offers a promising and practical solution for the efficient treatment and utilization of organic pollutants in water.

Sorption interactions and behavior of bentonite-lignite based composite toward immobilization of dyes, pharmaceuticals and surfactants

The presence of dyes, pharmaceuticals, and surfactants in the environment results from extensive industrial and societal progress, prompting the need to explore efficient and safe techniques for their removal. Common concentrations in wastewater can range from micrograms to milligrams per liter, which is concerning due to their persistence and potential health impacts. The sustainable approach of using a nonconventional, eco-friendly mineral-organic composite might address this environmental issue. This study focuses on utilizing a composite of bentonite (BEN) and lignite (LIG) as a sorbent for dyes: Rhodamine b (RB), Remazol brilliant blue r (RBBR), pharmaceuticals: ibuprofen (IB), sulfamethoxazole (STX), and surfactant: sodium dodecylbenzenesulfonate (SDBS) from both synthetic solutions and real wastewater. BEN was chosen for its high cation exchange capacity, while LIG was selected for its ability to adsorb both anionic and cationic formsdiverse functional groups. The composite with BEN to LIG ratio of 20:80 (BL 20:80) demonstrated superior sorption capacity. The adsorption performance is quantified, showing removal efficiencies of up to 18.9 mg RBBR/g, 22.8 mg RB/g, 1.77 mg IB/g, 1.47 mg STX/g, and 4.7 mg SDBS/g. Sorption efficiency is influenced by factors such as the initial sorbate concentration, the pH of the solution, the form of sorbates, and the adsorbents textural, physicochemical (point of zero charge pHZPC), ion-exchange capacity, hydrophobicity/hydrophilicity) properties. Generally, STX and RB is favored by slightly acidic conditions (pH 4–7), while RBBR and IB are favored by alkaline conditions (pH > 7). The complex physical sorption mechanism includes hydrogen bonding, electrostatic and dispersion forces, as well as π-π interactions. Nuclear magnetic resonance spectroscopy (NMR) suggests that a significant portion of the hydrogen bonding interactions contributes to RB adsorption. The sorption results indicate that the specially-designed mineral composite can effectively remove various chemically distinct organic compounds from real wastewater. Subsequent investigations will focus on the granulated BL 20:80 composite and its applicability in dynamic column systems. This aligns with the ongoing development of purification technologies.

Facile construction of ZnWO4/g-C3N4 heterojunction for the improved photocatalytic degradation of MB, RhB and mixed dyes

This study presents the construction of binary ZnWO4/g-C3N4 nanocomposite via a facile hydrothermal approach to enhance the photocatalytic performance under the visible light irradiation. The proposed ZnWO4/g-C3N4 nanocomposite photocatalyst shows excellent photodegradation towards organic dyes, such as methylene blue (MB) and rhodamine B (RhB). The optimal loading of ZnWO4 and g-C3N4 leads to the synergistic effect which plays a predominant role in inhibiting the fast electron-hole pairs recombination rate at the interface of ZnWO4/g-C3N4 photocatalyst. The degradation rates of MB and RhB is achieved around 92.9 % and 88.8 % under the visible light irradiation for 120 min. According to our findings, the radical quenching experiments suggested that the ●OH radicals played a positive impact in the photodegradation process. Since, our proposed photocatalyst exhibit superior photocatalytic activity towards the individual MB and RhB degradation. The ZnWO4/g-C3N4 photocatalyst were further applied to demonstrate the degradation of mixed dyes (MB and RhB) at an irradiation time of 180 min. In the mixed dye solution, the ZnWO4/g-C3N4 photocatalyst achieved a highest reaction rate of 0.010 min−1 for MB and 0.012 min−1 for RhB with the degradation rate of 87.8 % and 83.3 % for RhB and MB, respectively. For the mixed dyes, the radical quenching experiments confirmed that the ●OH radicals are responsible for the fast photodegradation. Additionally, the practicality of the proposed ZnWO4/g-C3N4 photocatalyst towards the degradation of MB, RhB and the mixed dyes were examined in the tap water samples. Furthermore, the plausible photodegradation mechanism of ZnWO4/g-C3N4 photocatalyst was proposed in detail. This study provides a new insight for the simultaneous degradation of mixed chemical pollutants using our proposed ZnWO4/g-C3N4 photocatalyst.

Synthesis, Characterization, and Application of La‐CNT in the Adsorption of Aqueous Rhodamine B Dye Solutions

AbstractResearchers have focused on exploring various types of nanomaterial‐based adsorbents, of which carbon nanotubes (CNT) are the most promising, to offset the harmful effects of waste water‐containing dyes on both human health and aquatic ecosystems. A new, novel, efficient, rapid, and one‐pot synthetic route for synthesizing CNT has been attempted by using sodium perchlorate as a precursor at 300 °C for 3 h. Further, La‐CNT (lanthanum‐doped carbon nanotubes) has been synthesized. These materials were characterized through FTIR, FESEM, XRD, STA, EDS, and UV‐visible techniques, among others. Both materials were used as better suitable and efficient adsorbents to completely remove the toxic dye Rh‐B (Rhodamine B) (≈100% adsorption of dye) from aqueous solutions. The synthesized materials displayed lanthanum‐doped carbon nanotubes and aligned nanotubes, with lanthanum‐doped carbon buds present in La‐CNT. La‐CNT was found to be more thermally stable than CNT. Freundlich and Langmuir's isotherms were validated for the adsorption process, with pseudo‐second‐order kinetics being favored.