The growing worldwide problem of wastewater management needs sustainable methods for conserving water supplies while addressing environmental and economic considerations. With the depletion of ...freshwater supplies, wastewater treatment has become critical. An effective solution is needed to efficiently treat the organic contaminants departing from wastewater treatment plants (WWTPs). Photocatalysis appears to be a viable method for eliminating these recalcitrant micropollutants. This study is focused on the degradation of Reactive Black 5 (
), a typical contaminant from textile waste, using a photocatalytic method. Titanium dioxide (TiO
) was deposited on a novel luminous fabric and illuminated using a light-emitting diode (LED). The pollutant degrading efficiency was evaluated for two different light sources: (i) a UV lamp as an external light source and (ii) a cold LED. Interestingly, the LED UV source design showed more promising results after thorough testing at various light levels. In fact, we note a 50% increase in mineralization rate when we triple the number of luminous tissues in the same volume of reactor, which showed a clear improvement with an increase in compactness.
This study investigates the pilot-scale combination of nonthermal plasma and photocatalysis for removing Toluene and dimethyl sulfur (DMDS), examining the influence of plasma energy and initial ...pollutant concentration on the performance and by-product formation in both pure compounds and mixtures. The results indicate a consistent 15% synergy effect, improving Toluene conversion rates compared to single systems. Ozone reduction and enhanced CO2 selectivity were observed when combining plasma and photocatalysis. This process effectively treats pollutant mixtures, even those containing sulfur compounds. Furthermore, tests confirm nonthermal plasma’s in-situ regeneration of the photocatalytic surface, providing a constant synergy effect.
•Red mud (RM) was used as a novel material for peroxymonosulfate (PMS) activation.•Hydroxylamine significantly enhanced flumequine (FLU) removal by the PMS/RM system.•Ciprofloxacin (CIP) and FLU were ...oxidized via ring cleavage, hydroxylation, decarbonylation, and defluorination.•Phosphate containing in hospital wastewater significantly inhibited the FLU removal.•Increasing PMS concentration and its sequential addition resulted in complete mineralization of FLU in HW.
In this study, a novel peroxymonosulfate (PMS) activation method, which combines a solid waste (i.e., red mud, RM) and a reducing agent (i.e., hydroxylamine, HA), for the oxidative degradation of fluoroquinolones (FQs; i.e., flumequine (FLU) and ciprofloxacin (CIP)) in hospital wastewater (HW) was developed. The addition of HA into the PMS/RM suspension significantly enhanced FLU removal, owing to its ability to enhance the Fe(III)/Fe(II) cycle on the RM surface. The results of the quenching experiments suggested the predominance of SO4•− over •OH in the PMS/RM/HA system. Moreover, owing to the greater reactivity between CIP and SO4•−, CIP removal was more effective than FLU removal. Additionally, the liquid chromatography-mass spectroscopy (LC-MS) analysis revealed that the oxidation of CIP and FLU by PMS/RM/HA occurred via sequential and separate processes, involving ring cleavage, hydroxylation, decarbonylation, and defluorination. Surprisingly, the wastewater components exhibited contrasting effects on FLU removal in HW. Natural organic matter, nitrate and sulfate showed a slight impact on the removal performance of FLU, whereas chloride improved the oxidation extent. However, phosphate significantly inhibited the FLU removal because of its competitive binding at the RM surface and its scavenging effect towards SO4•−. This inhibitory effect was overcome by increasing the PMS concentration and its sequential addition, thus guaranteeing successful mineralization of FLU in HW. These results show that the RM/HA system can be utilized to activate PMS for the removal of antibiotics in wastewater.
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•Laterite/PS/UVA is efficient to simultaneously remove three FQs.•Degradation rate constants can be ranked as follows: CIP > NOR > FLU.•Degradation and mineralization extents decrease ...in binary/ternary systems.•CIP oxidation in wastewater is less affected by FLU and NOR.•An excellent catalytic stability of laterite in mixture systems.
Although several emerging contaminants (e.g. fluoro(quinolones) (FQs)) have been simultaneously detected in environmental systems, there is very limited information on their elimination from contaminated waters in multi-component systems. In this study, removal of three FQs including flumequine (FLU), ciprofloxacin (CIP) and norfloxacin (NOR) were investigated in single and mixture systems, using natural laterite soil and persulfate (PS) under UVA irradiation. Both sorption and oxidation reactions contribute to the removal of FQs from aqueous phase, whereas quenching experiments showed that SO4− is mainly responsible for the FQs oxidation. The kinetic rate constants can be ranked as follows: CIP > NOR > FLU, regardless of whether the compound was alone or in mixture. The higher degradation rate constant of CIP relative to those of NOR and FLU could be explained by the high reactivity of SO4− radical with cyclopropane-ring containing compounds. Fall in oxidation performance was observed in synthetic wastewater, probably due to sulfate radical scavenging by wastewater components. However, degradation rate constants of CIP in wastewater remains unchanged in mixture systems as compared to single ones. This environmentally friendly remediation technology may appear as a promising way for the removal of fluoroquinolone antibiotics from multi-contaminated waters.
This study investigates and provides a solution for optimizing the photocatalytic treatment of toxic gases based on the use of TiO2 media deposited on luminous textiles. The target was the ...cyclohexane referent for the type A gas filtration tests. The photocatalytic supports were characterized by scanning electron microscopy. Then, the experiments conducted on a batch reactor showed that the TiO2-coated optical fiber media (in situ illumination configuration) performs better than conventional configuration (cellulosic TiO2 with external radiation "UV lamp". To take advantage of the new optical fiber media configuration, an intensification study was carried out by increasing the amount of TiO2 in the media and UV intensities of LED. Increasing these two parameters leads to an approximately fourfold increase in the degradation rate. The continuous treatment allowed the study to highlight the efficiency of the new configuration of the front flow reactors developed (PFR-LED) compared to the conventional configuration. This increased efficiency is demonstrated by the fourfold increase in the specific degradation rate of the optimized PFR-LED compared to the conventional reactor. The performance evaluation of the compact and optimized configurations of the frontal flow reactor (PFR-LED Optimized) aimed to highlight the influence of the inlet concentration under different flow rates. Furthermore, the effect of the number of optical fiber supports shows that the degradation rate and selectivity are enhanced. The results were obtained using four photocatalytic media (4OF/4UV-LED) for 1.19 mmol.m and#xfffd; 3 of cyclohexane input concentration at 18 L. min-1 of flow rate under optimal humidity conditions (38 %), constituting the ultimate rate of CO2 selectivity achieved (31 %) for an abatement of 59 %. This global investigation has allowed for the design of a new version of a compact reactor.This reactor provides an economical and efficient way to eliminate gaseous pollutants, which clearly meets the main aims of the UN Sustainable Development Goals (UN SDGs).
Hybrid non-thermal plasma combined with photocatalysis is an efficient technology for the degradation of volatile organic compounds (VOCs) and leads to a synergetic boosting effect of the degradation ...process. Herein, the degradation of ethylbenzene (EB) in a hybrid lab-scale reactor was performed. In the combined mode (plasma DBD and photocatalysis TiO2 + UVA), the degradation of EB was synergetically boosted, and a higher degradation efficiency was reached. In this study, the behavior of the synergetic effect was investigated whilst varying several operational conditions, including the UV light source (UVA and UVC), the TiO2 weight (7.5–22.51 g·m-²), the addition of metallic dopants to the TiO2 at different weight ratios (x%Cu-TiO2 and x%MnO2-TiO2, where x = 1, 3, 5 and 10 for the weight ratios of Cu:TiO2 and MnO2:TiO2) and the catalyst support (glass fiber tissue GFT and nickel foam NF with different thicknesses 0.3–3.3 mm). Moreover, the oxygen content (0–100%) in the reactor atmosphere was examined. The results showed an enhancement of the synergetic effect under UVC (TiO2 + UVC + DBD), which may be a consequence of intensive ozone decomposition under UVC and the generation of reactive atomic oxygen. The improvement of the synergetic effect under 1% Cu-TiO2 and 10% MnO2-TiO2 catalysts is assumed to reflect the role of metallic species in the production of oxygen species on the TiO2 surface via the ozone depletion mechanism. Furthermore, TiO2/NF (3.3 mm) showed the highest synergetic effect, likely due to the conductive character and the 3D porous structure of NF. Finally, the rich oxygen composition had an apparent impact on the synergetic effect.
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•Combination of DBD plasma with photocatalysis lead to high removal efficiency in the case of EB degradation.•The synergy effect of coupling DBD plasma with photocatalysis was evidenced.•Effect of experimental parameters on the variation of the synergetic effect was investigated for the first time.•Decomposition of ozone in the coupling process is confirmed as the source of the synergy effect.•Elucidating the source of the synergy effect allowed the optimization of plasma-photocatalysis process.
This review is aimed at researchers in air pollution control seeking to understand the latest advancements in volatile organic compound (VOC) removal. Implementing of plasma-catalysis technology for ...the removal of volatile organic compounds (VOCs) led to a significant boost in terms of degradation yield and mineralization rate with low by-product formation. The plasma-catalysis combination can be used in two distinct ways: (I) the catalyst is positioned downstream of the plasma discharge, known as the “post plasma catalysis configuration” (PPC), and (II) the catalyst is located in the plasma zone and exposed directly to the discharge, called “in plasma catalysis configuration” (IPC). Coupling these two technologies, especially for VOCs elimination has attracted the interest of many researchers in recent years. The term “synergy” is widely reported in their works and associated with the positive effect of the plasma catalysis combination. This review paper investigates the state of the art of newly published papers about catalysis, photocatalysis, non-thermal plasma, and their combination for VOC removal application. The focus is on understanding different synergy sources operating mutually between plasma and catalysis discussed and classified into two main parts: the effect of the plasma discharge on the catalyst and the effect of the catalyst on plasma discharge. This approach has the potential for application in air purification systems for industrial processes or indoor environments.
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•A 30-min plasma treatment at 200 °C induced the formation of crystalline particles of inverse spinel CoFe2O4, a phenomenon not observed in samples without plasma treatment.•Plasma ...treatment at 200 °C, a significant reduction in particle size was observed, with the average size plummeting to 6.7 nm, nearly three times smaller than the calcined sample at 600 °C (24.1 nm).•The plasma assisted synthesized material displayed remarkable magnetic properties, boasting a magnetization (Ms) of 91.80 emu/g and a coercivity (Hc) of 888 Oe. In stark contrast, the material calcined at 600 °C exhibited a lower magnetization of 64.53 emu/g and a higher coercivity of 1289 Oe.•EDX analysis unveiled surface oxygen defects in plasma synthesized material compared to materials synthesized by conventional calcination at 600 °C, resulting in a narrower bandgap (1.9 eV).•XPS analysis unveiled the presence of Co2+ and Co3+ within the spinel crystal structure of the plasma-treated material, elucidating the mechanisms underlying its enhanced magnetic behavior.
Non-thermal plasma (NTP)-assisted catalysis offers a promising avenue with diverse applications, particularly in air and water treatment. This study aimed to investigate the utilization of NTP discharge for the synthesis of magnetically active nanoparticles (MANps). We have demonstrated that the NTP discharge-assisted low-temperature calcination effectively induces surface modification and crystallization, thereby enhancing magnetic susceptibility. Specifically, a 30 min plasma treatment at 200 °C (CF-P-200) facilitated the formation of crystalline particles, a phenomenon that was absent in materials synthesized without plasma treatment under similar operating conditions. High-resolution microscopy revealed an average particle size of about 6.7 nm, while EDX analysis unveiled surface oxygen defects in CF-P-200 compared to materials synthesized by conventional calcination at 600 °C (CF-T-600), resulting in a narrower bandgap (1.9 eV). Magnetization measurements conducted using vibrating sample magnetometry (VSM) displayed superior magnetic properties of plasma treated MANps, with a magnetization (Ms) of 91.80 emu/g and coercivity (Hc) of 888 Oe. These values outperformed those of materials calcined at 600 °C (Ms: 64.53 emu/g, Hc: 1289 Oe), emphasizing the efficacy of NTP discharge in enhancing magnetic characteristics during material synthesis.
Sillenite materials have been the subject of intense investigation for recent years due to their unique characteristics. They possess a distinct structure with space group I23, allowing them to ...exhibit distinctive features, such as an electronic structure ideal for certain applications such as photocatalysis. The present research delves into the structure, synthesis, and properties of sillenites, highlighting their suitability for photocatalysis. It explores also advanced engineering strategies for designing sillenite-based photocatalysts, including heterojunction formation, morphology modification, doping, and hybrid processes. Each strategy offers advantages and limitations that are critically discussed. The review then lists and discusses the photocatalytic performance of various sillenite-based systems recently developed for common applications, such as removing hazardous organic and inorganic contaminants, and even infrequent applications, such as microbial inactivation, H2 generation, CO2 reduction and N2 fixation. Finally, valuable insights and suggestions are put forward for future research directions in the field of sillenite-based photocatalysis. This comprehensive overview would provide a valuable resource for the development of efficient photocatalytic systems to address environmental and energy challenges.
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•Recent concepts on various photocatalytic applications have been discussed.•Available synthesis techniques for sillenite materials have been covered.•The potential of sillenite crystals as photocatalysts has been explained.•Recent findings on using sillenite-based photocatalysts have been summarized.•Current approaches for enhancing the efficiency sillenites have been provided.
This study explores efficient Sicomet Green (SG) dye degradation using Fe(III)/Lig and Fe(II)/Lig complexes in modified photo-Fenton processes under UV, LED, and sunlight. Sunlight irradiation showed ...rapid kinetics with over 70% degradation efficiency. Multi-objective grey wolf optimization achieved 98% degradation and 96% mineralization yield using Fe(III)/Lig without pH adjustment. Inorganic ions inhibited the modified photo-Fenton process. A user-friendly app aided predictions and optimal parameters selection, emphasizing natural light sources and pH-neutral medium for dye removal through photo-Fenton.
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•Efficient SG dye degradation with Fe(III)/Lig & Fe(II)/Lig under sunlight.•Sunlight irradiation yielded rapid kinetics (>70% degradation efficiency).•MOGWO optimization achieved 98% degradation, 96% mineralization without pH adjustment.•Inorganic ions inhibited modified photo-Fenton process performance.•User-friendly app for accurate predictions & optimal parameters.
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