Treatment Of Pollutants In Wastewater Research Articles

Balanced adsorption and oxidation in a porous P, N-doped carbon prepared by melt-salt-mediated strategy for enhanced fenton-like reaction

The activation of persulfate oxidation processes using carbon-based catalysts is attractive for eliminating persistent aromatic organic pollutants in wastewater treatment. Herein, N and P co-doped carbonaceous (NPC) catalysts with an ultrahigh surface area were synthesized using a melt-salt-mediated strategy, employing Zeolitic Imidazolate Framework-8 as a self-sacrificing template. The NPC(1:1) carbon, prepared under optimized conditions, exhibited the highest surface area of 2001.5 m2/g, characterized by the highest number of defects and a high dispersion of N (1.89 %) and P (0.30 %) atoms on the carbon. This carbon catalyst exhibited a high capacity for adsorption and potential for activating persulfates in the removal of p-Nitrophenol (p-NP). Experimental data indicate a balance between adsorption and oxidation in the NPC(1:1)/PDS/p-NP system, with the highest catalytic removal rate achieved through moderate pre-adsorption of p-NP. Evidence from quenching, electron paramagnetic resonance (EPR), and amperometric i-t experiments suggests that the NPC(1:1)/PDS system primarily degrades p-NP through an electron transfer pathway. Defects in carbon and graphitic N were identified as catalytic sites. These defects resulted in an electron-deficient state, which leads to the activation of PDS and graphitic N was more reactive than both pyridinic and pyrrolic N in the adsorption of PDS molecules. Additionally, P-containing groups such as C-P-O, C-O-P, and C3-P were pinpointed as active sites on the carbons through DFT calculations. The intermediates during p-NP degradation were identified, and possible degradation pathways were proposed. A toxicity analysis indicated a significant reduction in overall toxicity following the oxidation treatment. This study provides innovative insights into the balance between adsorption and catalytic activity in porous carbon-activated persulfate oxidation reactions, thereby aiding in the development of enhanced oxidation catalysts for environmental remediation.

Green NiO nanoparticle-integrated PVA-alginate hydrogel: potent nanocatalyst for efficient reduction of anthropogenic water pollutants.

Hydrogel nanocatalyst composed of nickel oxide (NiO) nanoparticles embedded in PVA-alginate hydrogels were potentially explored toward the reduction of anthropogenic water pollutants. The NiO nanoparticleswas accomplished via green method using waste pineapple peel extract. The formation of the nanoparticles was affirmed from different analytical techniques such as UV-Vis, FTIR, XRD, TGA, FESEM, and EDS. Spherical NiO nanoparticles were obtained having an average size of 11.5nm. The nano NiO were then integrated into PVA-alginate hydrogel matrix forming a nanocomposite hydrogel (PVALg@ NiO). The integration of nano NiO rendered an improved thermal stability to the parent hydrogel. The PVALg@ NiO hydrogel was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP), potassium hexacyanoferrate (III), rhodamine B (RhB), methyl orange (MO), and malachite green (MG) in the presence of a reducing agent, i.e., NaBH4. Under optimized conditions, the reduction reactions were completed by 4.0min and 3.0min for 4-NP and potassium hexacyanoferrate (III), respectively, and the rate constant was estimated to be 1.14min-1 and 2.15min-1. The rate of reduction was found to be faster for the dyes and the respective rate constants were be 0.17s-1 for RhB, MG and 0.05s-1 for MO. The PVALg@ NiO hydrogel nanocatalyst demonstrated a recyclability of four runs without any perceptible diminution in its catalytic mettle. The efficacy of the PVALg@ NiO hydrogel nanocatalyst was further examined for the reduction of dyes in real water samples collected from different sources and the results affirm its high catalytic potential. Thus, this study paves the path for the development of a sustainable hydrogel nanocatalyst for reduction of hazardous pollutants in wastewater treatment.

Unmodified Mg/Al layered double hydroxide clay with versatile and specific adsorption capacity over high spectrum type of harmful contaminants

The present study investigates the effectiveness of Mg/Al layered double hydroxide (MATclay) for adsorbing Congo Red dye (CR) from wastewater. MATclay was prepared using a cost-effective co-precipitation method at pH 9.5, ensuring both chemical and mechanical stability. The in-depth physico-chemical characterization of MATclay sample was performed using various techniques, including FE-SEM, FT-IR, XRD, DLS, BET surface area, Zeta potential, TEM, XPS, XAS, and TGA. Batch experiments were performed to evaluate the adsorptive performance under different conditions (30–100 mg/L initial concentration, 298–320 K temperature range, and 5–180 min contact time). The adsorption data fit best with the Langmuir model, indicating monolayer adsorption with a maximum capacity of 60.61 mg/g. Post-adsorption analysis with SEM, XRD, and TGA confirmed the interaction of CR with MATclay. Furthermore, the MATclay material was applied as potential adsorbent for other type of pollutants, namely cationic dye (Methylene Blue) and antibiotics (Metronidazole, Tetracycline, and Cefotaxime), the data obtained in this complementary study showing good results for the removal of Tetracycline and Cefotaxime antibiotics. Overall, MATclay demonstrates potential as an effective adsorbent for CR dye and other pollutants in wastewater treatment.

Visible light-boosted photodegradation activity of Ag–AgVO3/Zn0.5Mn0.5Fe2O4 supported heterojunctions for effective degradation of organic contaminates

Abstract One of the most important concerns in developing efficient heterojunction photocatalysts for the photodegradation of environmental contaminants is the enhancement and acceleration of photocarrier separation. In this study, novel nanocomposite photocatalysts of Ag–AgVO3 nanorods grafted with Zn0.5Mn0.5Fe2O4 metal ferrites nanoparticles were developed by using facial hydrothermal and coprecipitation techniques for the effective photodegradation of Rhodamine B (Rh B) under visible light exposure. The fabricated materials were analyzed in detail using scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), nitrogen adsorption/desorption, transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), vibrating sample magnetometer, and ultraviolet–visible diffuse reflectance spectroscopy (DRS). The results showed an efficient contribution when compared to the earlier research. The TEM showed a hybrid of nanorods of supported composite with metal ferrite and Ag attached on the surface, consistent with field emission scanning electron microscopy and EDS results. The DRS expressed a lower band gap for supported nanocomposites (1.5 eV), which, arranged with PL, showed a lower recombination rate of supported nanocomposites. The surface properties showed that the supported hybrid might be as small as 45.42 nm or as large as 20.33 nm compared with others. When comparing the photocatalytic activity of pure AgVO3, Ag/AgVO3, and Zn0.5Mn0.5Fe2O4 photocatalysts, the performance of Ag–AgVO3/Zn0.5Mn0.5Fe2O4 nanocomposite photocatalyst was clearly superior (more than 99.9% degradation efficiency was achieved). The boosted activity the Ag–AgVO3/Zn0.5Mn0.5Fe2O4 photocatalyst system was justified by Z-system heterojunction induced by the plasmonic effect, and the suggested mechanism was investigated by quenching of reactive species by scavengers. The degradation performance was achieved under optimum conditions (pH = 2, 20 ppm of pollutant concentration, 120 mM of hydrogen peroxide, 1 g/L of catalysts dose). The results showed that after 240 min of visible irradiation resulted in the high (chemical oxygen demand) and (total organic carbon) reductions with a removal efficiency of (85) to (90%) for Rh B dye. The fabricated Ag–AgVO3/Zn0.5Mn0.5Fe2O4 nanocomposites were effective in the degradation of organic pollutants in wastewater treatment.

Water environment collaborative governance policy in the Yangtze River Delta

ABSTRACT Water environment collaborative governance is an important policy agenda during the Yangtze River Delta integration. Based on collaborative theory and policy value theory, this essay finds 144 water environment collaborative governance policies in the region from 2007 to 2022. It utilizes a policy collaborative model to discuss the water environment collaborative governance state at the regional and provincial levels in this region. Results show that 87.5% of water environment collaborative governance policies are enacted by local government in the region in this period, the main policy aims of which are water resource protection and wastewater pollution control. More policy attention will need to be paid to water environment restoration and off-office auditing of cadres. While administration policies and legal interventions are the main policy levers, economic policies and personal policies are relatively underused. Policy elements are significantly diversified at the provincial level in the region. In response to the findings above, this essay offers advice to improve water environment collaborative governance in the Yangtze River Delta region on four aspects: giving local governments full discretion in wastewater pollution treatment; giving full play of the water pollution control policies' value; adopting differentiated water pollution control policies; and strategies among the local government in the region, exerting policy stability.

Modulation of metal-organic frameworks by anionic surfactants for rapid adsorption of organic pollutants bisphenol A and chrome black T

With the accelerated development of industry, which generates large quantities of sewage discharged into the aquatic environment, serious impacts on both environmental and human health. Detecting various organic contaminants in water sources has become common, presenting huge challenges for water treatment. Metal-organic frameworks are characterized by their rich porous structures and high chemical activity, making them ideal adsorbents for removing organic pollutants from water. In this study, sodium dodecylbenzene sulfonate is added to the precursor solution of MIL-101(Cr)-Cl2 and synthesized hierarchical porous structure adsorbents MIL-SDBS-X, using hydrothermal synthesis to enhance their adsorption capacity, making efficient and rapid removal of bisphenol A(BPA) and chromium black T(EBT), two common organic pollutants in water, which MIL-SDBS-0.7 was the most effective. MIL-SDBS-0.7 exhibites great potential in the adsorption of BPA and EBT for its high adsorption capacity (260.5 mg-1·g-1 and 272.3 mg-1·g-1) and rapid adsorption (equilibrium could be achieved in 15 minutes), The findings reveal adsorption kinetics aligns with the pseudo-second-order model and the Langmuir equation best fits to study adsorption of MIL-SDBS-0.7 to BPA and EBT. Thermodynamic parameters affirm the exothermic and higher spontaneity behavior of the adsorption process. Moreover, the adsorption mechanism of MIL-SDBS-0.7 was explored, illustrating the crucial roles of effects of hydrogen bonding π-π stacking and pore filling in the adsorption of BPA and EBT. Therefore, this work not only provided a convenient strategy for the preparation of efficient and fast MIL-SDBS-0.7 hierarchical porous material but also highlighted the promising potential of synthesized absorbents as an effective adsorbent for organic pollutants in wastewater treatment and environmental remediation.

Comparative study of photocatalysis with bulk and nanosheet graphitic carbon nitrides enhanced with silver

The main goal of this research is to investigate the effectiveness of graphitic carbon nitride (g-C3N4, g-CN) in both bulk and nanosheet forms, which have been surface-modified with silver nanoparticles (Ag NPs), as photocatalysts for the degradation of acid orange 7 (AO7), a model dye. The photodegradation of AO7 dye molecules in water was used to test the potential photocatalytic properties of these powder materials under two different lamps with wavelengths of 368 nm (UV light) and 420 nm (VIS light). To produce Ag NPs (Ag content 0.5, 1.5, and 3 wt%) on the g-CN materials, a new synthesis route based on a wet and low-temperature method was proposed, eliminating the need for reducing agents. The photodegradation activity of the samples increased with increasing silver content, with the best photocatalytic performances achieved for bulk g-CN samples and nanosheet silver-modified samples (with the highest content of 3 wt% Ag) under UV light, i.e., more than 75% and 78%, respectively. The VIS-induced photocatalytic activity of both examined series was higher than that of UV. The highest activities of 92% and 98% were achieved for the 1.5% Ag-modified g-CN bulk and nanosheet materials. This research presents an innovative, affordable, and environmentally friendly chemical approach to synthesizing photocatalysts that can be used for degrading organic pollutants in wastewater treatment.

Heterogeneous sulfate radical-mediated benzotriazole oxidation by ferrospinel nanoparticles catalyzed peroxymonosulfate: A catalyst for environmental remediation

The sulfate radical-based advanced oxidation process has been widely investigated via peroxymonosulfate (PMS) activation in recent years, in which the development of catalysts with high efficiency and stability is crucial. The current work prepared a series of magnetic nanoparticles, including CuFe2O4 (CuF) and CoFe2O4 (CoF), for benzotriazole (BTA) degradation via PMS activation. Various techniques (XRD, VSM, BET, FESEM, and TEM) employed to examine the physicochemical, textural, magnetic, and structural characteristics of the as-prepared catalysts. Moreover, a response surface methodology (RSM) based on central composite design (CCD) used to identify the optimum levels of operational variables and explore the interactions between them. The results showed that 99.7 and 100% of BTA can be removed under optimal conditions when CuF and CoF catalysts were applied in the system in the presence of PMS, respectively. Both catalysts exhibited high degradation efficiencies, even after eight consecutive cycles, highlighting their high stability and reusability in decontamination applications. According to the trapping tests, HO• and SO4•– species were responsible for the BTA degradation in both systems. These results suggested that CuF and CoF could be applied as effective recoverable catalysts for activating PMS and degrading persistent pollutants in wastewater treatment.

Enhanced catalytic degradation of organic dye by Sn1-xLaxO2 nanoparticles under UV light for wastewater treatment

Effectively eliminating dyes and heavy metals from wastewater, without secondary contamination and with easy recovery, is a significant challenge. To address this, SnO2-based photocatalysts were fabricated using a straightforward sol–gel method, aiming to achieve high-value reutilization and environmental protection. Utilizing XRD, FTIR, and HRTEM, the investigation has conclusively confirmed the emergence of nanoparticles (NPs) through rigorous analysis and observation techniques. Raman, XPS, and PL spectroscopy probed electronic, optical properties, and lattice defects, offering comprehensive insights into material characteristics. Specific BET surface areas were observed to be 17.72 and 39.64 m2/g for 0 % and 5 % La samples. The introduction of dopant La to the SnO2 lattice resulted in enhanced optical properties, demonstrated by a significant red shift. La-SnO2 nanoparticles demonstrated remarkable catalytic efficacy, degrading 94 % of RB dye solution under 60 min of UV light exposure. Even after four cycles, the catalytic degradation activity remained high at 87 %, showcasing excellent structural stability. Enhanced adsorption capacity and effective separation of electron-hole pairs under light contribute to this improvement. Moreover, the study delved into defect-based room temperature ferromagnetism (RTFM) by examining the formation of a novel network, such as La3+-O-Sn4+. The results highlight the potential of these composites doped photocatalysts as effective materials for degrading harmful organic pollutants in wastewater treatment and for their application in spintronic devices. The present study aims to characterize the structural, magnetic, and optical attributes of La-doped SnO2 nanoparticles.

Dual-functional electrocatalyst of defective cobalt-nitrogen-doped porous carbon for enhanced in-situ hydrogen peroxide generation and electro-Fenton tetracycline degradation

Tetracycline hydrochloride (TC) is one of the organic pollutants that can be consistently monitored in the aquatic environment and pose a great threat to the environment. The development of a bifunctional electro-Fenton (EF) catalyst capable of in situ H2O2 production and decomposition to ·OH to degrade the pollutant is an efficient and green approach to deal with antibiotic pollution. The bifunctional catalysts Co, N double doped defective carbon materials were prepared by pyrolysis ball milling method using zeolite imidazolium ester skeleton structural materials (ZIFs) series materials as precursors, which showed more than 80% selectivity to H2O2 and could basically remove TC within 120 min in EF system. Carbon defects and graphitic nitrogen can effectively improve the selectivity and yield of H2O2, while graphitization degree improves the charge transfer rate, the doping of Co and pyridinic-N contribute to the decomposition of H2O2 into ·OH. The active species present in the Co1/Zn1-NPC/EF system is ·OH, and factors such as coexisting ions, humic acid and water quality have little effect on the efficiency of the degradation of TC in the Co1/Zn1-NPC/EF system, whereas Co1/Zn1-NPC electrocatalytic catalyst has excellent stability and stable treatment performance for a wide range of pollutants, as well as being an environmentally friendly green catalyst without metal leaching. Furthermore, the possible pathways and the toxicity hazard of TC degradation were proposed. The bifunctional electrocatalyst prepared in this research provides a novel strategy for the green and efficient treatment of pollutants in wastewater.

Construction of S scheme ZnO/g-C3N4 heterojunction for the removal of pyridine from coal chemical wastewater

In order to achieve the removal of nitrogen-containing heterocyclic compound pyridine in coal chemical wastewater. The S scheme ZnO/g-C3N4 heterojunction was constructed by evaporation solvent-high temperature thermal polymerization. The construction of the S scheme heterojunction effectively improved the photocatalytic activity. The S scheme heterojunction well retained the h+ with high oxidation activity of ZnO-VB and the e− with high reduction activity of g–C3N4–CB, achieving efficient separation of e−-h+. The complex band structure and potential difference lead to the bending of the band and the formation of the internal electric field, which effectively realizes the charge separation. ZnO/g-C3N4 heterojunction shows good activity and stability, and has great potential in the field of organic pollutant wastewater treatment. The construction of S scheme heterojunction also provides a new way to improve the activity of photocatalyst.

Efficient removal of Congo Red by carbonized Ganoderma lucidum spore with Fe3O4

In this study, a biomass carbon magnetic adsorbent (Fe3O4@GLSM) was prepared by using carbonized G. lucidum spores and Fe3O4 nanoparticles. Scanning and transmission electron microscopy proved that the G. lucidum spores after carbonization (GLSM) have hollow cage structure and increased surface depression. X-ray diffraction, X-ray photoelectron spectroscopy, and vibrating sample magnetometer analysis demonstrated that magnetic Fe3O4 nanoparticles were successfully loaded on GLSM. We have investigated the affective adsorption factors of contact time, pH, and adsorbent dose on the adsorption properties of CR from aqueous solution. Adsorption process is less affected by acidity and alkalinity and can reach to adsorption equilibrium. The maximum Fe3O4@GLSM adsorption capacity is 58.4 mg. The kinetic data for the adsorption of CR were well fitted by the pseudo-second-order kinetic equation. The intra-particle diffusion model showed that the adsorption involved surface adsorption followed by diffusion. Freundlich isotherm models provided a more accurate representation of sorption isotherms than Langmuir model. The adsorption thermodynamics (ΔGθ, ΔHθ and ΔSθ) established that CR adsorption onto Fe3O4@GLSM was spontaneous and feasible. This novel magnetic biomass adsorbent can potentially serve as an effective method for removing and rapidly separating pollutants in wastewater treatment.

Exploring the peroxydisulfate activation by carbon nanotubes for pollutants degradation: Identification of the primary reaction mechanism and key molecular descriptor

Carbon nanotubes (CNT) have been proposed to activate persulfate over the past decade, resulting in successful degradation performance for organic pollutants in wastewater treatment. However, there is debate over the reaction mechanism involving radical versus non-radical pathways, setting up a roadblock to further developing persulfate activation by carbonaceous materials. This work focused on the carbon nanotubes/peroxydisulfate (CNT/PDS) system, investigated its reaction mechanism, and unveiled the relationship from the aspect of molecular descriptors. The involvement of radicals (e.g., SO4•− and HO•) and 1O2 was ruled out by the observation of quenching effect, oxidation products, chemical probes, solvent exchange, and electron paramagnetic resonance spectra. Then, mediated electron transfer was deemed as the primary reaction mechanism based on linear sweep voltammetry analysis, which was supported by the PDS consumption result. The substrate-dependent treatment capacity was found in the CNT/PDS for multiple contaminants degradation, and it turned out that EB3LYP was the most significant parameter in the relationship between degradation rates and molecular descriptors. Outstanding environmental application was exhibited based on the coexistence of various organic/inorganic substances and repeated degradation experiment. Therefore, the findings from this study would be helpful for both scientific research and technical development of persulfate activation by CNT.

Green Synthesis of Silver Nanoparticles using Lawsonia inermis for Enhanced Degradation of Organic Pollutants in Wastewater Treatment

<p>In response to the growing demand for eco-friendly and efficient catalysts in wastewater treatment, this study introduces a novel, biosynthesized silver nanoparticle (AgNP) using leaf extract from Lawsonia inermis, a widely available plant. We employed a unique concentration mixture of 0.015 mg/mL leaf extract and 2.0 mM silver nitrate to achieve optimal results under atmospheric conditions. Comprehensive characterization was conducted through X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and ultraviolet-visible absorption spectroscopy. Remarkably, these Lawsonia inermis-synthesized AgNPs (LI-AgNPs) demonstrated superior catalytic degradation of organic pollutants, such as 4-nitrophenol, methylene blue, eosin yellow, and methyl orange. Among them, 4-nitrophenol was reduced most efficiently, following pseudo-first order kinetics. The LI-AgNPs exhibited unprecedented catalytic potential, evidenced by a sharp decline in methyl orange absorption and the emergence of a new hydrazine compound signal at 280 nm. With a catalytic loading as low as 0.2 mg/mL, we achieved an astounding 82.5% dye removal. This innovative approach advances the field of environmental remediation</p>

Involvement of Fenton Reaction on Biodecolorization and Biodegradation of Methylene Blue Dye by Brown Rot Fungi <i>Daedalea dickinsii</i>

The disposal of dye wastewater has become a major global concern. Meanwhile, microorganisms have shown high potential in the treatment of wastewater pollutants. In this study, the involvement of the Fenton reaction in the biodecolorization and biodegradation of methylene blue (MB) by the brown rot fungus Daedalea dickinsii was investigated. Subsequently, D. dickinsii is a fungus capable of producing hydroxyl radicals (•OH). This experiment was conducted with an initial MB concentration of 75 mg/L, and different incubation times of 0, 7, 14, 21, and 28 d respectively. The result showed that the Fenton reaction played an important role, and this was demonstrated by the addition of FeSO4 as a Fe2+ source. The removal of MB by D. dickinsii with the addition of Fe2+ reached 91.454% at 28 d in a mineral salt medium. It was higher compared to D. dickinsii culture treatment without Fe2+ addition, 86.427%. Furthermore, the metabolic degradation product was analyzed using LC-TOF/MS and identified as 2-amino-3-hydroxy-5-(methylamino) benzenesulfonic acid and N-(3,4-dihydroxy phenyl)-N-methyl formamide.

Strongly piezocatalytic dye decomposition of sol-gel synthesized PZT film

Piezocatalysis technology emerges as a promising solution for environmental protection and wastewater pollution treatment. This study focuses on the synthesis of Pb(Zr0.50Ti0.50)O3 (PZT) ferroelectric thin films as piezocatalysts through a sol-gel method. The piezocatalytic performance of these PZT films under vibration is also evaluated through utilizing Rhodamine B(RhB) dye as a model pollutant. When vibrations are applied to the RhB solution for 3 h, the RhB dye decomposition ratio reaches 90.22 %. The influence of pH values, vibration power and dye concentration condition on the decomposition ratio of RhB dye wastewater during the piezocatalytic process. Furtherly, these inhibitor experiments indicate that these middlle active species in piezocatalysis of PZT film are mainly the ·O2− and ·OH radicals. The study demonstrates the tremendous potential of PZT film's piezoelectric effect in treating dye wastewater through harvesting mechanical vibration energy.

Hierarchical Ti3C2/CdIn2S4 micro-flower facilitates enhanced tetracycline degradation and Cr(VI) reduction

Developing of a photocatalyst for the degradation and reduction of high concentrated pollutants from wastewater is of great importance. 2D/2D flower-like Ti3C2/CdIn2S4 (MXCIS) was successfully prepared by integrating Ti3C2 and CdIn2S4 using a hydrothermal method. MXCIS-8 possess the best photocatalytic activity, and its removal efficiency of 50 mg/L of TC and Cr (VI) can reach 80.4% and 60.8%, respectively. This is caused by the Schottky heterostructure with the well 2D/2D interface, which can boost its photon capture performance and effectively hinder the recombination of photo-generated electrons and holes. Hydroxyl radicals, superoxide radicals, and h+ participate in the TC degradation, and both acidic and alkaline conditions are conducive to enhancing the degradation activity of MXCIS-8. However, only e− is the main contributor to the Cr(VI) reduction, and the photocatalytic performance of MXCIS-8 decreases under alkaline conditions. Importantly, MXCIS-8 exhibits satisfactory physicochemical stability, recyclability, and environmental friendliness. Overall, this work confirms that MXCIS has broad application potential in the removal of Cr (VI) and TC pollutants in wastewater treatment.

Unveiling the photocatalytic property of La2O3–CuO nanocomposites for organic pollutants in wastewater treatment

Photocatalytic degradation was considered the best strategy for removing hazardous dye contaminants in water bodies from wastewater. The photocatalyst of pure La2O3 nanoparticles and La2O3–CuO nanocomposites synthesized by sonochemical method. The nanocomposites were used to investigate the degradation activity of Safranin (SR) and crystal violet (CV) under sunlight irradiation. The physicochemical characterization methods (e.g., Field emission scanning electron microscopy (FESEM), high resolution-transmission electron microscopy (HR-TEM), ultraviolet, visible spectroscopy (UV–Vis), and BET analysis indicate that the composite has been constructed successfully that enhances the widened visible light absorption, induces charge transfer and separation efficiency of electron–hole pairs. X-ray diffraction (XRD) experiment demonstrated that introducing copper into lanthanum resulted in alterations in the size of the crystallites and the average size of the nanoparticles, shifting from 21.93 to 43.19 nm. The photocatalytic activity of all samples was examined through the photodegradation of Safranin and crystal violet in an aqueous medium. The photocatalytic degradation rate of nanocomposite catalysts could eliminate 95.80 % and 97.05 % of Safranin and crystal violet dyes in 135 min, about 1.4 times that of pure La2O3 nanoparticles. The current study will give an efficient nanocomposite photocatalyst for removing biological and textile dye aqueous pollutants.

Monolithic CoMgAl mixed metal oxide nanosheets on Al2O3 granules for the efficient advanced oxidation process

Cobalt-based catalysts are good candidates for the degradation of organic pollutants in wastewater treatment due to their high activity, while powdered catalysts for practical applications face challenges like difficulty in regeneration. To solve the problem, this work designs a monolithic catalyst by in-situ growth of CoMgAl mixed metal oxide (CoMgAl-MMO) nanosheets on the Al2O3 granules. The obtained catalyst possesses a developed mesoporous structure with highly-dispersed Co on the surface. The catalytic activity of CoMgAl-MMO/AG in the dye degradation is dependent on the Co/Mg molar ratio. All monolithic catalysts show high degradation performance, of which the CoMgAl-MMO/AG catalyst with Co/Mg ratio of 0.8/1.2 exhibited the highest degradation rate, achieving 95 % acid orange (AO7) removal in 10 min testing.

Development of a new composite LDH/TiO2-3D for degradation of sulfaguanidine under UV and visible light: Experimental design, kinetic and mechanisms

Constructing 3D heterostructures has been considered an effective approach to enhance the photocatalytic activity of materials. However, the preparation of 3D heterostructures is always a complex process. In this paper, three-dimensional (3D) spherical TiO2 immobilized on Cu3AlCO3 Layered Double Hydroxides (LDH) was successfully synthesized using the impregnation method. The structure, morphology, and property of Cu3AlCO3-LDH/xTiO2-3D were investigated by X-ray diffraction (XRD), FTIR spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), UV-Visible diffuse reflectance spectroscopy. The photocatalytic properties of composite materials were evaluated by degradation of sulfaguanidine (SGD) antibiotic under simulated solar irradiation. To optimize the photocatalysis process, an experimental design methodology was used. The experimental design utilized in most published works involves simple matrices that focus on quantitative factors. In contrast, our work enables the study of both qualitative factors (dissolved oxygen concentration) and quantitative factors (pH, catalyst dose and temperature) for both responses using a mixed matrix (D‐optimal) and a multiplicative model. To achieve this, 22 Run of experiments designed by the AZURAD® software. The optimal values of pH, catalyst dose, temperature, and dissolved oxygen concentration were found to be 8, 0.23 g.L−1, 25 °C, and 2 mg.L−1, respectively. The transformation product and possible degradation pathways of SGD were identified through Orbitrap LC/MS. Additionally, the present composite photocatalysts exhibited satisfactory re-usability for at least four cycles. Due to the facile synthesis process, higher photocatalytic activity under visible light irradiation and satisfactory re-usability, these composites can be considered as potential catalysts for degrading pharmaceutical pollutants in wastewater treatment.