Treatment Of Pollutants In Wastewater Research Articles

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.

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 (260.5mg-1·g-1 and 272.3mg-1·g-1) and rapid adsorption (equilibrium could be achieved in 15minutes), 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.

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.

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

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) were 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) was 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 the 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.

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.

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.

Ammonium changes the pathway of tetrabromobisphenol S degradation by sulfate radical oxidation

Sulfate radical (SO4•-)-based advanced oxidation processes (SR-AOPs) show great potential in the elimination of organic pollutants in wastewater treatment and groundwater remediation. Tetrabromobisphenol S (TBBPS) as an emerging contaminant can be effectively degraded in SR-AOPs. However, the present study found that SO4•- also reacted with ammonium (NH4+), a ubiquitous inorganic nitrogen species in aquatic environments, thus markedly affected the rates and pathways of TBBPS degradation in SR-AOPs. TBBPS underwent β-scission and debromination upon SO4•- attack, leading to various transformation products. The released bromide (Br-) underwent further oxidation by SO4•- to form free bromine which reacted with certain TBBPS intermediates, generating disinfection byproducts (DBPs). When NH4+ was present in such system, the abatement of TBBPS was apparently suppressed. Meanwhile, NH4+ was oxidized by SO4•- to nitrogen dioxide radical (NO2•) which coupled with certain radical intermediates of TBBPS oxidation, yielding nitrophenolic products including 2,6-dibromo-4-nitrophenol (DBNP) and mono-nitro substituted TBBPS. When 10 μM TBBPS was treated by heat activated peroxydisulfate with 1 mM NH4+, the molar yield of DBNP reached 22% in 2 h. More importantly, NH4+ scavenged the in situ formed free bromine to form monobromamine (NH2Br), decreasing regulated DBPs formation but leading to highly toxic dibromoacetonitrile (DBAN). This study broadens the understanding of interactions between the transformation of halogens and NH4+ during SO4•- oxidation. It also reveals the potential environmental risks when SR-AOPs are employed for the organohalogen pollutants degradation in realistic environments where NH4+ is present.

Valorization of spent Aureobasidium pullulans for the removal of toxic pollutant in wastewater treatment

Textile industries are growing rapidly due to increased demand for textile products worldwide. The discharge of textile effluent containing synthetic dyes, chlorides, pigments, aromatic compounds, and heavy metals contributes substantially to water pollution due to its toxicity and chemical composition. This work is focused on the potential usage of treated Aureobasidium pullulans biomass (TAPB) to remove the toxic chemical pollutant, Methylene Blue (MB), from an aqueous solution. Experimental results found that maximum MB removal of 76.5% was observed using TAPB dosage of 3 ​g/L, initial pH 8.0, temperature 30 ​°C, and initial MB concentration of 50 ​mg/L. The maximum biosorption capacity of TAPB was found to be 113.75 ​mg/g using the Langmuir non-linear approach. Successive biosorption and desorption experiments showed better regeneration capacity of TAPB until the fourth trial. These results demonstrated that maximum MB removal (%) could be possible with a small quantity of biomass, consequently offering a minimum size of the contactor and less capital cost requirement for biosorption. It also showed a greater regeneration capacity biosorbent for removing MB. Hence, the feedstock consumption for MB removal could be considerably decreased in large-scale processes.

Enhanced Photocatalytic Degradation of Malachite Green Dye Using Silver-Manganese Oxide Nanoparticles.

Efficient and excellent nanoparticles are required for the degradation of organic dyes in photocatalysis. In this study, silver-manganese oxide nanoparticles (Ag-Mn-NPs) were synthesized through a wet chemical precipitation method and characterized as an advanced catalyst that has enhanced photocatalytic activity under sunlight irradiation. The nanoparticles were characterized using scanning electron microscopy (SEM), XRD, UV-vis light spectra, and energy-dispersive X-ray (EDX) spectroscopy, revealing their spherical and agglomerated form. The EDX spectra confirmed the composition of the nanoparticles, indicating their presence in oxide form. These bimetallic oxide nanoparticles were employed as photocatalysts for the degradation of malachite green (MG) dye under sunlight irradiation in an aqueous medium. The study investigated the effects of various parameters, such as irradiation time, catalyst dosage, recovered catalyst dosage, dye concentration, and pH, on the dye's photodegradation. The results showed that Ag-Mn oxide nanoparticles exhibited high photocatalytic activity, degrading 92% of the dye in 100 min. A longer irradiation time led to increased dye degradation. Moreover, a higher catalyst dosage resulted in a higher dye degradation percentage, with 91% degradation achieved using 0.0017 g of the photocatalyst in 60 min. Increasing the pH of the medium also enhanced the dye degradation, with 99% degradation achieved at pH 10 in 60 min. However, the photodegradation rate decreased with increasing dye concentration. The Ag-Mn oxide nanoparticles demonstrate excellent potential as a reliable visible-light-responsive photocatalyst for the efficient degradation of organic pollutants in wastewater treatment.

Pollutant Burden on Pollution Sources in the Wai Batu Merah Watershed, Sirimau District, Ambon City

This study aims to identify sources of pollution and determine the magnitude of the potential pollution load from pollutant sources in the Wai Batu Merah watershed, Sirimau District, Ambon City. The method for identifying sources of pollution is carried out by using saturated or census sampling methods, calculating pollutant loads using direct methods for point source pollutant sources and indirect methods for non-point sources . The direct calculation method uses wastewater discharge data and the results of wastewater quality analysis results from measurements directly at the point source pollutant wastewater treatment plant (WWTP). The wastewater sampling technique uses the grab sampling method. While the indirect method uses effluent factors and supporting data from non-point source pollution sources that have been identified in the Wai Batu Merah watershed. The results showed that the pollutant sources found in the Wai Batu Merah watershed were point sources originating from hotel and health facility activities and non-point sources originating from domestic activities from residential areas, agricultural and livestock businesses, non-point source land (forest and open land), micro, small and medium enterprises (MSMEs), small scale industries and waste. The dominant pollutant source in the Wai Batu Merah watershed comes from domestic non-point sources. The highest point source pollution loads for BOD, COD and TSS parameters in the Wai Batu Merah watershed came from hotel activities in segment 6 with the contribution of each parameter of 17.82 kg/day, 23.82 kg/day and 0.029 kg/day. Meanwhile, the highest non-point source pollution load for BOD, COD and TSS parameters came from non-point source waste in segment 6 with the contribution of each parameter of 2825.3 kg/day, 3884.8 kg/day and 2684.03 kg/day.

Self-cleaning photoelectrocatalytic filtration based on Ca(OH)2/Ti3C2Tx composite nanofiltration membranes for synergistically enhanced separation and degradation of phenolic compounds

Combining photoelectrocatalytic (PEC) and nanofiltration (NF) membranes has emerged as an attractive technology for removing organic pollutants in wastewater treatment, however, the separation and degradation performance are still challenging. Herein, novel composite NF membranes were constructed by cross-linking a Ca(OH)2/Ti3C2Tx (CT) catalyst to a polyamide membrane using tannic acid (TA). In these CT@TA (CTTP) membranes, Ti3C2Tx reduces the charge-transfer resistance and recombination rate of CT, leading to enhanced PEC activity. The optimal CTTP membrane had a high water flux (27.9 L·m−2·h−1·bar−1) and excellent rejection rates for phenolic compounds (phenol: 85.1 %, 4-nitrophenol: 91.1 %, and bisphenol A (BPA): 94.6 %). Under visible-light irradiation with electrical assistance (3 V), the BPA degradation rate (92.2 %) was 13.7 % higher than that under light irradiation alone, and a higher flux recovery rate was achieved (94.1 %). Superoxide (O2−) and hydroxyl (OH) radicals were critical active species in catalytic BPA degradation, and the observed intermediates suggested that the degradation pathway involves oxidation, hydroxylation, and aromatic ring cracking. The developed NF membranes, which exhibit synergistic separation and degradation effects and self-cleaning properties, provide an innovative solution for the treatment of organic pollutants in wastewater.

Aplikasi Fotokatalis TiO2 Dan Alternatifnya Untuk Degradasi Pewarna Sintesis Dalam Limbah Cair

Liquid waste containing synthetic dyes is a significant environmental problem, particularly in the textile industry, such as batik waste. Recent studies have shown the potential of TiO2 photocatalysis in reducing color and Chemical Oxygen Demand (COD) in such waste. In addition to TiO2, ZnO nanoparticles and ZrO2-TiO2 composites have also been tested as alternative photocatalysts for the degradation of synthetic dyes. The use of immobilized TiO2 nanoparticles on various substrates such as plastic sheets, hydrogels, or hybrid films has increased the efficiency of photocatalytic processes and allowed for the separation of photocatalysts from the waste after treatment. Furthermore, the combination of TiO2 with additives such as Mg, Ag, and Fe has enhanced the photocatalytic performance in removing synthetic dyes from wastewater. The use of TiO2-based photocatalytic membranes also enables simultaneous filtration and degradation of pollutants in wastewater treatment. In addition to degrading synthetic dyes, TiO2 photocatalysis has been successfully used to remove natural dyes like Congo red from industrial wastewater. Recent studies have also explored new synthesis methods to obtain TiO2 photocatalysts with enhanced properties, such as TiO2 nanocoating on nanocomposites or TiO2 nanocoating on porous materials. Overall, these studies demonstrate that TiO2 photocatalysis has great potential in liquid waste treatment, particularly in the degradation of synthetic dyes found in textile industry waste like batik waste.