Removal Of Organic Pollutants Research Articles

Ti3+ Self-Doping of TiO2 Boosts Its Photocatalytic Performance: A Synergistic Mechanism

Pollution remains one of the most significant global challenges. Photocatalysis consists of a new organic pollutant removal technology, with TiO2 widely studied as a photocatalyst in the photocatalytic removal of water pollution. However, intrinsic TiO2 has the disadvantages of weak visible light absorption, low electron separation, and transmission efficiency, as well as few active sites. In this study, anatase-phase Ti3+ self-doped TiO2 (B-TiO2) with a core-shell structure was successfully prepared by forming an amorphous layer rich in oxygen vacancies (OVs) and Ti3+ defects on the TiO2 surface under a nitrogen atmosphere using NaBH4 as a chemical-reducing agent. The visible light absorption performance of the catalyst was notably improved when exposed to light irradiation. The bending of surface energy bands facilitated the separation of photogenerated electron-hole pairs, and the core-shell structure allowed the electron-hole pairs to be transported to the surface of the catalyst and participate in the reaction faster. We observed that 92.86% of Rhodamine B (RhB) was degraded in only 5 min, an increase of 2.73 times that of the degradation rate observed in commercial P25. With extraordinary stability, the photocatalytic efficiency of the catalyst remained at 96.2% after five degradation cycles.

Cloud point extraction of heavy metal ions for wastewater remediation: an equilibrium and kinetic study

Abstract Surfactants offer a promising alternative for the efficient and environmentally friendly removal of organic pollutants and toxic heavy metal ions from various media. Their high efficiency and environmental compatibility make them a valuable option for remediation efforts. This study focuses on the cloud point extraction (CPE) of ions from aqueous solutions using biodegradable nonionic surfactants combined with ionic surfactants instead of chelating agents. Phase diagrams of binary surfactant/water systems were first constructed. The effects of salt, inorganic contaminants, and ionic surfactants on the cloud point (Tc) were then investigated. At temperatures above the cloud point, two distinct phenomena were observed and monitored over time: phase separation and phase clarification. The kinetic process was studied using the Turbiscan Lab Expert. Extraction results were evaluated based on four responses: extraction yield (E%), residual concentrations of solute (Xs,w) and surfactant (Xt,w) in the dilute phase, and volume fraction of coacervate at equilibrium (Φ C). Empirical modelling gives a satisfactory agreement between experimental and calculated values. The capacity of CPE to simultaneously remove an organic pollutant and a toxic heavy metal was demonstrated.

Covalent Organic Framework Packed Nanoporous Membrane for Continuous Removal of Bisphenol A from Agricultural Irrigation Wastewater.

BPA, a typical endocrine disruptor, poses a significant threat to the growth of crops and thereby jeopardizes sustainable agriculture products and human health. In this work, a water-stabilized imine covalent organic framework (TpBD-COF) packed nanochannel membrane was constructed. The TpBD-COF membrane achieves high selective removal of BPA attributed to the subdivision of the pores by the filled COF, which further reduces the porous size and effectively eliminates the distance barrier between the selective sites of TpBD-COF membranes and BPA. The selective removal ratio of BPA was 5.79 times higher than that of the bare membrane, while the removal capacity reached 6.78 nM cm-2 min-1. It can eliminate BPA from irrigation wastewater and ensure crop growth. The application of COF-filled nanoporous membrane provides not only a size-matching strategy for the development of specific continuous removal of BPA but also a theoretical reference for membrane removal of other organic pollutants in agricultural irrigation water environment.

Recent development on neem (azadirachta indica) biomass absorbent: surface modifications and its applications in water remediation

This review paper discusses the latest advances in transfiguring Azadirachta indica (neem) biomass into an adsorbent and how it can be used to clean the environment. As an economical and environmentally favorable adsorbent material, neem biomass has become increasingly popular due to its bioactive properties and abundance. The review breaks down modification techniques into chemical and physical processes. Important physical changes covered include preactivation, carbonization, and using fluidized bed technologies and rotary kilns. It has been shown that these methods greatly improve the surface properties of neem biomass, which makes it better at absorbing things and holding more. The changes that were made also have an effect on the adsorption kinetics and isotherms, which helps us understand the adsorption rates and equilibrium behaviors of the changed adsorbents better. Neem biomass adsorbents are illustrated through their versatility and efficacy in the removal of organic pollutants, dyes, and heavy metals from effluent. This is illustrated through specific applications. Additionally, computational studies and artificial intelligence are looked into to see if they can help us understand how adsorption works at the molecular level, improve the efficiency of modification processes, and guess how adsorption will behave. The review also talks about the research gaps and suggests areas for future research. The review emphasizes the crucial importance of integrating experimental and computational methods to enhance the performance of the modified neem biomass and increase its environmental cleaning potential.

A portable bifunctional platform of aluminum/alkalized carbon nitride/silver for sensitive SERS detection and efficient photocatalytic degradation of malachite green

It is necessary to construct a portable bifunctional substrate with high-repeatability and low-cost for detection and degradation of pollutants in practical applications. Herein, the alkalized carbon nitride (ACN) is assembled onto the etched aluminum sheet (EAl) by hydrogen bonding self-assembly which induces the porous structure of EAl/ACN. Subsequently, Ag nanoparticles (AgNPs) are mainly in-situ embedded in the cavities of EAl/ACN, and finally a portable bifunctional substrate of EAl/ACN/Ag is constructed. The surface-enhanced Raman scattering (SERS) response of the EAl/ACN/Ag is highly sensitive and selective for detection of malachite green (MG), and the limit for MG can reach 5.53 × 10-13 mol/L with an enhancement factor (EF) of 2.95 × 105. In addition, the EAl/ACN/Ag substrate shows excellent homogeneity, stability, recyclability and reproducibility. Moreover, the EAl/ACN/Ag substrate displays a high photocatalytic degradation efficiency of 96.4 % for MG within 50 mins even if it is reused for five cycles. Therefore, the developed portable bifunctional substrate shows bright prospects for the detection and removal of organic pollutants in the fields of industrial wastewater analysis.

Effective adsorptive removal of heavy metal anion Cr(Ⅵ) and dye cation methylene blue by the novel 2D material TiVCTx MXene

With the increasingly serious industrial pollution, the effective removal of heavy metal ions and organic pollutants from wastewater has become a key issue of environmental protection. In this paper, a new MXene material, TiVCTx, was prepared by in situ etching, and its adsorption capacity of heavy metal anion Cr(Ⅵ) and methylene blue (MB) dye cation was studied. The effect of adsorption time, pH values, temperatures, initial concentrations of adsorbent and adsorbate, interfering ions on the Cr(Ⅵ) and MB adsorption of TiVCTx was systematically investigated. It is found that TiVCTx has excellent Cr(Ⅵ) and MB adsorption property, the adsorption capacity can be as high as 600mg/g and 1430mg/g, respectively. The adsorption experiments revealed that the adsorption process of Cr(Ⅵ) conformed to the Langmuir isotherm model and the Pseudo-second-order kinetic model, which indicated that the Cr(Ⅵ) adsorption was a heat-absorbing monolayer chemisorption. In contrast, the adsorption process of MB is in accordance with the Freundlich isotherm model and the Pseudo-second-order kinetic model, suggesting that the MB adsorption was an exothermic multilayer chemisorption. The results of X-ray electron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis further confirmed that the reductive adsorption and electrostatic adsorption can account for the outstanding Cr(VI) and MB adsorption capacity of TiVCTx, respectively.

Waste lignocellulosic biomass-derived graphitic carbon encased bimetallic nickel‑palladium oxide nanofibers for efficient organic dye pollutant removal and antibacterial actions

Waste lignocellulosic biomass-derived graphitic carbon encased bimetallic nickel‑palladium oxide nanofibers for efficient organic dye pollutant removal and antibacterial actions

Novel visible-light-driven I- doped Bi2O2CO3 nano-sheets fabricated via an ion exchange route for dye and phenol removal

Here, we developed a novel visible-light-driven I- doped Bi2O2CO3 nano-sheet photocatalyst fabricated via a facile ion exchange route at room temperature. This obtained Bi2O2CO3 nano-sheets with I- doping showed several advantages. The specific surface area of I0.875-Bi2O2CO3 was 2.16 times higher than that of Bi2O2CO3, providing more catalytic site for degradation reactions. Moreover, a 3.2 times photocurrent enhancement was observed in I0.875-Bi2O2CO3 comparing with Bi2O2CO3, producing more photogenerated electron-hole pairs for degradation reactions. The synergistic effect between texture property and photoelectric effect boosted the removal of organic pollutants. Under visible light illumination, I0.875-Bi2O2CO3 displayed superior photocatalytic performance for degradation of methyl orange and phenol. Notably, a phenol degradation rate of 88% was achieved over I0.875-Bi2O2CO3 with illuminating for 60 min, which was about 29 times higher than Bi2O2CO3. This finding may provide an opportunity to develop a promising I- doped catalyst for organic pollutants removal.

A comprehensive review of production and characterization of biochar for removal of organic pollutants from water and wastewater

A comprehensive review of production and characterization of biochar for removal of organic pollutants from water and wastewater

S-scheme QDs-sized photocatalyst fabricated through combination of TiO2-x with gray BiOCl for efficient removal of organic pollutants upon visible light

S-scheme QDs-sized photocatalyst fabricated through combination of TiO2-x with gray BiOCl for efficient removal of organic pollutants upon visible light

Exploration of bismuth based perovskite materials for organic dyes removal from waste water

The scourge of water pollution due to organic matter is a well-known fact. In order to address this issue, we employed a highly facile method of solid state reaction for the synthesis of bismuth potassium titanate, Bi0.5K0.5TiO3 (BKT) photocatalyst. Furthermore, the bandgap tailoring of the BKT is performed by photo-reduction of Ag onto the BKT, which results in the formation of hetero-structure junctions at the surface of the BKT. The as-prepared BKT and BKT-Ag photocatalysts are systematically characterized by x-ray diffraction, scanning electron microscopy, and high resolution transmission electron spectroscopy. Furthermore, the photocatalyst activity of the BKT and BKT-Ag was analyzed against the target organic pollutants by using UV–Vis spectroscopy. Three organic dyes such as methylene blue, eriochrome Black T, and methylene orange (MO) were used as target organic pollutants. The anchoring of Ag for the formation of hetero-structure junctions at the surface of BKT rendered it to be an ideal photo-catalyst with a bandgap reduction from 3.37 to 2.08 eV. Therefore, lowering the bandgap resulted in enhanced photocatalytic activity of the BKT-Ag. Among the three target dyes, BKT-Ag showed remarkable photo-degradation of MO and Erb T by degrading ≥90% of MO and Erb T in 120 min at neutral pH values. It is believed that BKT based photocatalysts can provide a unique platform for the removal of organic pollutants from wastewater.

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) derived from cobalt/iron solid complex as peroxymonosulfate (PMS) activator for efficient bensulfuron-methyl degradation

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) was synthesized by convenient solid phase coordination combined with calcination method to activate PMS for the degradation of BSM. A series of Co/Fe bimetallic oxides with different metal ratios were designed and prepared to select the most efficient catalyst and Fe2O3-CoO@NC(Co:Fe = 1:1) demonstrated the highest catalytic activity and the lowest ions leaching. The reasons for high catalytic activity of Fe2O3-CoO@NC(Co:Fe = 1:1) were evaluated by a range of characterization techniques and the results showed it stemmed from higher mental content and larger current density. Complete (100%) degradation of 10 g L−1 BSM was achieved within 10 min under the conditions of 0.05 g L−1 catalyst and 0.3 mmol/L PMS dosage at 25 °C. Moreover, Fe2O3-CoO@NC(Co:Fe = 1:1) showed more excellent catalytic activity and lower ions leaching than Fe2O3, CoO and Fe2O3-CoO, indicating superior bimetallic synergy and carbon encapsulation effect. Furtherly, radical experiments and XPS analysis revealed the main active species and catalytic mechanism of the Fe2O3-CoO@NC/PMS system, respectively. Finally, the degradation pathway of BSM by Fe2O3-CoO@NC/PMS system was deduced by LC-TOF-MS. This paper is aimed to provide a new insight into the convenient preparation method for the construction of catalysts which could reach efficient removal of complex organic pollutants.

WS2-Assisted Electrochemical Activation of Peroxymonosulfate for Eliminating Organic Pollutant in Water

Advanced oxidation process based on heterogeneous activation of peroxymonosulfate (PMS) has received significant attention in wastewater remediation. Herein, a facile and effective electrochemical method was introduced in a tungsten sulfide (WS2)-activated PMS process for the removal of a typical azo dye Acid Orange 7 (AO7) in aqueous solution. It was found that the electrochemical activation could remarkably promote the removal of organic pollutants by coupling with WS2/PMS system. The elimination of AO7 in the electro-assisted WS2-activated PMS (E/WS2/PMS) system achieved 95.8% of AO7 removal in 30 min, with the optimal conditions of 1.0 g/L WS2, 1.0 mM PMS, current density of 1.0 mA/cm2 and initial pH of 6.5. Based on quenching experiments and EPR techniques, mechanistic studies confirmed that hydroxyl radical (•OH) and singlet oxygen (1O2) are the primary reactive oxygen species for the oxidation of pollutants. In addition, the influences of pH, WS2 dosage, PMS concentration, current density, common anions and humic acid on the AO7 removal are also investigated in detail. Furthermore, the system exhibited resistance to aqueous matrices, verifying the accepted applicability in real water (i.e., Yangtze River water and Shahu Lake water). In summary, this study demonstrates a green system for the effective removal of contaminants in water, holding significant implications for practical application.

Insights into the low-temperature rapid catalytic pyrolysis and remediation mechanism of weathered petroleum-contaminated saline-alkali soil using Beta zeolite

Pyrolysis technique is considered to have great potential in the remediation of petroleum-contaminated soil, but it still has difficulties such as high energy consumption for the degradation of complex petroleum hydrocarbons and the deterioration of soil quality after treatment. In this study, the low-temperature rapid catalytic pyrolysis was realized using Beta zeolite to assist in remediating weathered petroleum-contaminated saline-alkali soil. Under the action of Beta zeolite, the removal efficiency of petroleum hydrocarbons reached 81% after pyrolysis treatment for 10 min at 250 °C, which was reduced to regulatory standard. The pyrolysis behavior and mechanism revealed that the addition of Beta zeolite effectively reduced the activation energy of C-C and C-O bonds cleavage in petroleum hydrocarbon macromolecules due to the strong acidity of Beta, meanwhile the quality of recovered oil from pyrolysis was improved. Additionally, the analyses of soil physicochemical property indicated that the harmless graphitic C generated from the degradation of petroleum hydrocarbons increased the organic matter in the soil, and the addition of Beta zeolite enhanced soil water retention capacity and reduced the soil alkalinity, thus improving the ecological function of saline-alkali soil. This study provides a new strategy for the removal of organic pollutants under special soil media conditions.

Conservation translocations in urban environments: State of the knowledge and future directions

Cities are important for biodiversity conservation and are a central focus in the United Nations Decade of Ecosystem Restoration. Species reintroductions and population reinforcements (i.e. conservation translocations) are an important component of conservation, yet are rare in urban environments, possibly because of perceived risks in highly modified and complex social-ecological urban systems. Here we review the literature describing urban conservation translocations to provide guidance for their effective implementation. We find that urban translocations have been performed for a variety of aims including focal species conservation, improvements in ecosystem functions in the later stages of restoration projects (e.g. seed dispersal in revegetated sites) and for site remediation (e.g. organic pollution removal), and enhancing human-nature connections. Conservation translocations were found in a range of urban habitat types including formal and informal greenspaces, grey spaces, streams, ponds, and marine environments, ranging from near-historic conditions (e.g. remnant/restored sites) to highly modified novel/designed systems. Barriers and enablers varied between terrestrial and aquatic release sites, with predators, habitat suitability, and leaving release sites being more important in terrestrial sites and disturbance (flooding) regime and pollution being more important in aquatic sites. A range of techniques have been applied to mitigate these barriers. Success rates in urban translocations are high (>90 %) and comparable to conservation translocations in general, suggesting they can contribute to urban biodiversity conservation by assisting species to overcome dispersal barriers and occupy otherwise suitable urban habitats. However, evaluation methods vary widely between urban translocation studies. There is also a need for longer-term monitoring of translocation success that might be achieved simultaneously while enhancing human-nature connections through citizen science programs.

Performance of Dye-Containing Wastewater Treatment Using MnxOy-Catalyzed Persulfate Oxidation

Dye wastewater is characterized by high salinity, intense coloration, difficulty in degradation, and complex organic compositions, posing significant environmental risks. Manganese oxide (MnxOy)-based materials have been widely used for the removal of recalcitrant organic pollutants in water environments. In this study, various MnxOy polymorphs were prepared, and their catalytic activities for persulfate (PS) activation were evaluated using Orange II (AO7) as a model molecule. After 50 min treatment, the degradation efficiency of AO7 ranked as α-MnO2/PS > γ-MnO2/PS > β-MnO2/PS > Mn2O3/PS, with α-MnO2/PS achieving the highest efficiency of 98.6%. XPS, XRD, and electrochemical analyses indicated that α-MnO2 exhibited an exceptional crystal structure and performance. The α-MnO2/PS system exhibited a strong pH adaptability across a wide pH range of 3.0–9.0. The presence of coexisting anions at 0.1 mM, including Cl−, NO3−, CO32−, and SO42−, slightly reduced the degradation rate of AO7. The reactive oxygen species, mainly SO4•− and 1O2, predominantly destroyed the naphthalene ring structure of AO7. Furthermore, α-MnO2 exhibited an excellent stability, allowing for multiple reuse cycles without interference from common anions in water, highlighting its strong potential for practical applications. These results provided insights into the environmental fates of AO7 in the α-MnO2/PS system.

Facile synthesis of bio-carbon supported cobalt hexacyanoferrate hybrid photocatalyst for effective removal of hazardous organic pollutants

Facile synthesis of bio-carbon supported cobalt hexacyanoferrate hybrid photocatalyst for effective removal of hazardous organic pollutants

Synthesis and evaluation of MMT/TiO2 nanotube photocatalysts for enhanced degradation of organic dyes in wastewater

This study aims to synthesize a nanocomposite photocatalyst from naturally sourced clay (montmorillonite, MMT) and titanium dioxide nanotubes (TNTs) to efficiently degrade organic dyes in wastewater under UVC light. The TNTs were synthesized through the hydrothermal method and were randomly attached to both the surface and interlayer spaces of the MMT sheets. Pristine MMT was found to exhibit good adsorption properties, while the TNTs demonstrated strong photocatalytic activity. The combination of these materials in the MMT/TNT nanocomposite resulted in a material that exhibited both adsorption and photocatalytic properties. The dye degradation efficiency of the MMT/TNT nanocomposite reached 95%, which is significantly higher than that of pristine MMT (50%) and TNTs alone (60%). This enhanced performance can be attributed to the synergistic effect between the adsorption capacity of MMT and the photocatalytic activity of TNTs. The study highlights the potential of using naturally sourced materials like MMT in the development of advanced photocatalysts for environmental remediation. The MMT/TNT nanocomposite offers a sustainable and efficient solution for the removal of organic pollutants from wastewater. These findings provide a pathway for further development of high-performance nanocomposites that combine the dual functional properties of adsorption and photocatalysis, contributing to more efficient wastewater treatment technologies.

Recyclable palladium nanocatalyst for effective organic pollutants removal through reduction☆

Palladium is a metal catalyst with excellent performance, but its application is severely restricted due to low atomic utilization and weak recovery capacity. To address these issues, we prepared a palladium nanocatalyst through a universal nanocatalysts preparation strategy. It has a particle size of less than 100 nm, possesses good superparamagnetism, and its saturation strength is 71.48 emu/g. It demonstrates outstanding catalytic properties in the reduction and decolorization of organic fuels, and the achieving conversion rates are 92 %, 99 %, and 97 % for methylene blue, rhodamine B, and methyl orange, respectively. Additionally, it can catalyze the hydrogenation dehalogenation of p-chlorophenol, with a 100 % conversion rate and selectivity. The nanocatalyst shows outstanding recyclability in the test of recyclability. Therefore, our results show that the palladium nanocatalysts have attractive characteristics of simple preparation, excellent catalytic activity and reusability. This work lays the foundation for the preparation of palladium nanocatalysts and their potential applications in areas like environmental pollution treatment.

Sulfonate-Bonded Conjugated Microporous Polymer Hollowed-Out Spheres to Capture Fluoroquinolone Antibiotics and Cationic Dyes from Wastewater.

Developing adsorbent materials for the efficient removal of multiple organic pollutants in water is of importance technological significance. In the present work, a kind of conjugated microporous polymer (CMP) with a hollow sphere structure was constructed by applying SiO2 nanoparticles as a template and 1,3,5-triethynylbenzene (TEB) and 2,7-dibromocarbazole (27-DBCZ) as building blocks via the Sonogashira-Hagihara cross-coupling reaction. In order to further improve the dispersibility of the as-resulting CMPs in water, hydrophilic CMPs (H-S-CMPs) were obtained by a sulfonation modification. The adsorption performance of H-S-CMPs on dyes and antibiotics was investigated, which was based on different experimental parameters such as the initial concentration, contact time, temperature, pH, and adsorbent dose. The adsorption isotherm, kinetics, and thermodynamics were also studied, and the possible adsorption mechanism of H-S-CMPs was discussed. The experimental results illustrated that the adsorption process of H-S-CMPs on dyes and antibiotics is more consistent with the Langmuir isotherm model and the pseudo-second-order kinetic model. The maximum adsorption capacities of H-S-CMPs for rhodamine B (RhB), methylene blue (MB), ciprofloxacin, and norfloxacin were 206.2, 324.7, 222.2, and 216.9 mg/g, respectively, which were determined according to the Langmuir isothern model. In addition, the adsorption mechanism of H-S-CMPs may be attributed to the synergistic effects of hydrogen bonding, electrostatic attraction, π-π stacking, and pore filling. After 5 cycles, H-S-CMPs still maintained good stability, and their removal rate of dyes could reach more than 70%. Notably, this polymeric hollow microsphere has been less extensively investigated as an adsorbent for the removal of dyes and antibiotics. As a result, based on the designable flexibility of CMPs and the unique structure of hollow microspheres, the material holds great promise for wastewater treatment in the presence of multiple pollutants.