Catalytic Degradation Of Organic Pollutants Research Articles

Waste to worth: Facile preparation of CaO2 derived from oyster shells for highly efficient degradation of organic contaminants based on Fenton-like system

In recent years, CaO2 has been frequently used as a substitute for H2O2 to address the limitations of H2O2. However, commercially available CaO2 are facing the shortcomings of low purity and limited preparation conditions. Oyster shells can provide superior and abundant biomass calcium element with low cost for developing CaO2. In this work, highly purified CaO2 functional biomaterials were prepared via a facile approach derived from waste oyster shells, which were applied in a Fenton-like system to remove organic pollutants. Experimental results indicated that the oyster shells-derived CaO2 with 100% purity exhibited a greatly enhanced catalytic performance compared with other CaO2 materials in Fenton-like catalytic degradation of organic pollutants, which can be completely removed within 60 s. The high purity of CaO2 would facilitate the release of H2O2 during the Fenton-like catalytic reaction and promote the generation of more active species to oxidize pollutants. Besides, the abundant trace metal elements originated from oyster shells can further motivate the Fenton-like reaction and accelerate the degradation of pollutants, endowing oyster shells-derived CaO2 an excellent catalytic activity. Furthermore, the Fenton-like catalytic mechanism was proposed on basis of tests of radicals trapping and electron spin resonance, validating the vital roles of ⋅OH, ⋅O2– and 1O2 generated throughout the reaction process. This work not only provides a novel and low-cost approach to exploit CaO2 with highly efficient catalytic ability, but also realizes the effective resource utilization of waste shells.

Highly-efficient persulfate activation by nitrogen-doped biochar derived from dewatered sewage sludge for 2,4-dichlorophenol removal: Process and mechanism

Sewage sludge represents a promising substrate, meriting investigation for its nutrient content and potential for repurposing. Nitrogen-doped biochar (NSC) was synthesized from dewatered sludge over a range of pyrolysis temperatures, spanning 400–800 ℃. This study explores the efficacy of NSC in enhancing the removal of 2,4-dichlorophenol (2,4-DCP) through the integrated processes of adsorption and persulfate (PS) activation, marking its inaugural investigation in this work. The adsorption behavior was best described by both the pseudo-second-order kinetic model and the Freundlich isotherm model. Under conditions with an unadjusted pH value, [PS] at 2 mM, [NSC] at 5 g/L, and [2,4-DCP] at 100 mg/L, the NSC800 (pyrolyzed at 800 ℃)/PS system achieved a complete removal of 2,4-DCP within 120 minutes. The results from radical quenching tests, electron paramagnetic resonance (EPR), and electrochemical analysis indicated that 2,4-DCP degradation occurred via both radical and non-radical mechanisms. Among the nitrogen species, graphitic N was identified as the predominant PS activation site. The NSC800/PS system demonstrated notable catalytic efficiency and stability in the removal of 2,4-DCP, maintaining its efficacy in the presence of Cl-, NO3-, H2PO4-, and CO32-. Significantly, the optimal reaction stoichiometric efficiency (RSE = 72.059%) was observed at the minimal PS concentration. This research introduces a novel methodology for municipal sludge valorization, proposing an economical biochar designed for the combined adsorption and catalytic degradation of organic pollutants.

Research Progress on the Degradation of Organic Pollutants in Water by Activated Persulfate Using Biochar-Loaded Nano Zero-Valent Iron.

Biochar (BC) is a new type of carbon material with a high specific surface area, porous structure, and good adsorption capacity, which can effectively adsorb and enrich organic pollutants. Meanwhile, nano zero-valent iron (nZVI) has excellent catalytic activity and can rapidly degrade organic pollutants through reduction and oxidation reactions. The combined utilization of BC and nZVI can not only give full play to their advantages in the adsorption and catalytic degradation of organic pollutants, but also help to reduce the agglomeration of nZVI, thus improving its efficiency in water treatment and providing strong technical support for water resources protection and environmental quality improvement. This article provides a detailed introduction to the preparation method and characterization technology, reaction mechanism, influencing factors, and specific applications of BC and nZVI, and elaborates on the research progress of BC-nZVI in activating persulfate (PS) to degrade organic pollutants in water. It has been proven experimentally that BC-nZVI can effectively remove phenols, dyes, pesticides, and other organic pollutants. Meanwhile, in response to the existing problems in current research, this article proposes future research directions and challenges, and summarizes the application prospects and development trends of BC-nZVI in water treatment. In summary, BC-nZVI-activated PS is an efficient technology for degrading organic pollutants in water, providing an effective solution for protecting water resources and improving environmental quality, and has significant application value.

Manganese Oxide Hydrogel for Efficient Removal of Volatile Organic Compound in the Photothermal Water Purification

In recent years, the photothermal evaporation technology that effectively solves the problem of fresh water shortage has attracted great interest, but the problem is that volatile organic compounds (VOCs) always enter the condensate with vapor during the evaporation process, so the combination of photothermal evaporation and photocatalysis is considered. Herein, narrow‐bandgap β‐MnO2 is selected as the material for photothermal evaporation and catalysis, and a β‐MnO2 porous hydrogel (β‐MnO2‐PH) interfacial evaporator with high evaporation efficiency and catalytic degradation of organic pollutants is designed using porous and hydrophilic hydrogels as carriers. The optimized evaporation rate can reach 3.5 kg m−2 h−1 and achieve high light absorption of 93.4% in the full spectral range. This is better than the performance of most MnO2‐based solar evaporator reported so far. In addition, β‐MnO2‐PH has the function of photocatalytic purification and effectively degrades VOCs such as phenol. By combining photothermal action of evaporator with photocatalytic performance, it provides unlimited potential application in solar desalination and industrial wastewater treatment.

Tuning intramolecular charge transfer of covalent organic frameworks with triazine structure for enhanced peroxymonosulfate activation performance on the catalytic degradation of organic pollutants under visible light irradiation

As emerging metal-free photocatalysts, covalent organic framework with triazine structure (CTF) hold great potential for refractory organic pollutants removal in the visible-light-induced peroxymonosulfate system (PMS/Vis). In this work, the electron-withdrawing group(ketone structure) was introduced into the CTF framework (keto-CTF), aiming to regulate the regional electronic structure of CTF and thus further enhancing its visible-light photocatalytic performance and PMS activation. The results showed that the introduction of ketone greatly enhanced the visible-light utilization, carrier separation and intramolecular charge transfer capabilities of CTF. Notably, the keto-CTF/PMS/Vis system with resistance to environmental factors exhibited highly efficient and stable catalytic performance for the degradation and mineralization of organic pollutants, which was superior to that of single catalytic system. Indeed, the excellent photocatalytic performance and PMS activation of keto-CTF were attributed to the enriched valence-electron density around O atoms of ketone compared to that of C atoms, which led to a multitude of internal electric fields within the keto-CTF consisting of positive and negative electric centers. These internal electric fields not only promoted the separation and intramolecular transfer of photogenerated charges but enhanced the adsorption of PMS onto keto-CTF. The adsorbed PMS subsequently captured photogenerated charges, further reducing electron-hole recombination in keto-CTF and generating various reactive species. Ultimately, the efficient degradation of organic pollutants was achieved via the co-dominance of hole and singlet oxygen with the assistance of the charge-transfer-based non-radical pathway. This work provides new insights into the visible-light-induced multi-path catalytic oxidation mechanism of PMS and provides an effective solution for the removal of refractory organic pollutants from wastewater.

Covalent Organic Framework Impregnated with Silver and Copper Nanoparticles: An Advanced Approach for Catalytic Degradation of Organic Pollutants in Wastewater.

In this study, we introduce an economically viable and scalable process for developing a novel covalent organic framework (COF), which is a cross-linked polymer. The resulting material, TzTFB-COF, is successfully functionalized with silver and copper nanoparticles, which show high adequacy in the degradation of nitroaromatic compounds (NACs). For the synthesis of TzTFB-COF, s-tetrazine diamine (Tz) and 1,3,5-triformylbenzene (TFB) are chosen as building blocks, which exhibit a high density of nitrogen-containing sites. TzTFB-COF shows good chemical and thermal stability (>300 °C). For functionalization of TzTFB-COF with silver and copper nanoparticles, a solution infiltration technique is used. The composite materials, i.e., Ag@TzTFB-COF and Cu@TzTFB-COF, have been characterized using various spectroscopic and analytical techniques, which show high activity, high selectivity, and excellent chemical and thermal stability up to 350 °C. The silver and copper contents of Ag@TzTFB-COF and Cu@TzTFB-COF are determined to be 9.6 and 12.4 wt % by inductively coupled plasma optical emission spectrometer (ICP-OES). The catalytic efficiency of the synthesized Ag@TzTFB-COF and Cu@TzTFB-COF materials is assessed in the context of catalyzing the hydrogenation of NACs. Experimental results reveal a remarkable catalytic performance when conducted in an aqueous medium, and notably, the materials demonstrate substantial potential for reusability across multiple catalytic cycles. The determined parameters for the catalytic hydrogenation reaction, i.e., the rate constants and Gibbs free energies, are found to be 0.0185 s-1 and 9.878 kJ/mol for Ag@TzTFB-COF and 0.0219 s-1 and 9.615 kJ/mol for Cu@TzTFB-COF. Thus, the catalytic reaction exhibits characteristics of endothermic, endergonic, and nonspontaneous nature.

Microwave-Assisted Fabrication of Pd, Co and Ni Nanoparticles Modified-SiO2; as Catalysts in the Reduction Reaction of Organic Pollutants

Nanomaterials have been used in catalytic degradation of organic pollutants also act as catalysts in for many years. Due to excellent catalytic performances of metal-based nanoparticles, these materials have been used extensively in various hybrid catalyst synthesis. The main subject of this study, heterogeneous catalysis is a low cost and multi-purpose process for many pollutants. Catalytic degradation of organic pollutants such as; 2-Nitrophenol, Quinolin Yellow and Rhodamine B was investigated by using Ni, Co, Pd nanoparticles modified SiO2 based nanomaterials. The co-doping effect on the prepared nanomaterials has been investigated with different characterization methods in terms of structural and morphological features: scanning electron microscopy, UV/Vis absorption spectroscopy, energy-dispersive X-ray spectroscopy and foruier-transform infrared spectroscopy. The highest catalytic reduction efficiencies (97.6% and 97.5%) for 2-nitrophenol and Rhodamine B was obtained by Pd-PEG-AP@SiO2 respectively. The synthesized Co-PEG-AP@SiO2 illustrated higher catalytic reduction efficiency for Quinolin Yellow (70.1%) at the end of 60s. The prepared M-PEG-AP@SiO2 nanomaterial (M: Pd,Co,Ni) can be able to utilized degradation of organic contaminants effectively.

Catalytic degradation of acetaminophen by C and O co-doped graphitic carbon Nitride: Peroxymonosulfate vs. Peroxydisulfate

Though peroxymonosulfate (PMS) and peroxydisulfate (PDS) have been studied for catalytic degradation of organic pollutants, much to be elucidated for the differences of them. In this study, they were used in acetaminophen (ACT) removal, activated by C and O co-doped graphitic carbon nitride (CN) (COCN), and the performance and mechanisms were comparatively investigated. COCN had more defects and O-containing groups, and showed higher reactivity than O-doped CN (OCN). COCN/PMS was greatly superior to COCN/PDS in ACT removal, because of faster and more adsorption of PMS than PDS onto COCN. 1O2 generation on C = O and electron transfer were dominantly responsible in both systems, but were much more and faster in COCN/PMS than in COCN/PDS. In addition, O2− was involved in 1O2 generation only in COCN/PMS, while persistent free radicals in COCN were reacted only with PDS. Both systems share similar ACT degradation pathways and changes in COCN properties after uses. The potential in practical applications was verified by the performance in the presence of co-existing ions and natural organic matter, and in real wastewater. It is believed that this study would provide new insights into the differences between PMS and PDS, in the degradation of organic pollutants using carbonaceous materials.

Enriched adsorption and photocatalytic Fenton catalytic degradation of organic pollutants by CuBi2O4 loaded non-metallic modified graphene composite hydrogels

Adsorption and advanced oxidation technology are important means to remove organic pollutants, and the combination of adsorption and catalytic degradation to construct a multi-field coupled system can realize valid adsorption and degradation of organic contaminants. In this paper, CuBi2O4 supported by a nonmetallic element-modified graphene hydrogel composite structure CuBi2O4/X-rGH (X = N, P, S, B) was synthesized and applied to the efficient removal of organic pollutants. We found that the doping of nonmetallic elements enhances the graphene conjugated large π-bond system, which not only improves the adsorption performance of pollutants but also increases the graphene conductivity and builds more carrier transport channels, which is beneficial to the photocatalytic Fenton synergistic degradation activity. Among them, CuBi2O4/P-rGH could achieve 90 % degradation of phenol (50 ppm) after 20 min of turning on the light, which was nearly 2 times more than the degradation activity of CuBi2O4/rGH. Electron paramagnetic resonance (EPR) and quenching experiments proved that ·OH was the main active species in the synergistic degradation process, and the mechanism of adsorption of nonmetallic modified graphene hydrogel hybrid catalysts and in situ photocatalytic Fenton degradation of pollutants was proposed.

Peak-like three-dimensional CoFe2O4/carbon nanotube decorated bamboo fabrics for simultaneous solar-thermal evaporation of water and photocatalytic degradation of bisphenol A

Catalytic CoFe2O4 and solar-thermal carbon nanotube decorated bamboo fabrics (CCBF) are fabricated for integrating efficient solar steam generation from wastewater with catalytic degradation of its organic contaminants. Thanks to the numerous porous channels and polar groups of bamboo fabric and the efficient solar-thermal energy conversion of black carbon nanotubes, the porous and hydrophilic CCBF exhibits fast upward transport of water, efficient solar light absorption, and high solar-thermal energy conversion efficiency. The decorated CoFe2O4 not only enhances the solar-thermal energy conversion efficiency of CCBF but also activates potassium peroxymonosulfate to generate abundant highly active species for catalytic degradation of bisphenol A (BPA). Furthermore, folding the CCBF into a peak-like 3D evaporator can enhance solar energy utilization, and gain environmental energy for promoting solar-thermal water evaporation and catalytic degradation performances. The 3D CCBF evaporator achieves a water evaporation rate of 2.72 kg m–2 h–1 under 1-sun irradiation. Meanwhile, 100% of the BPA in the seawater can be degraded within 10 min. An exceptional high purification efficiency of 27.72 kg m–2 h–1 is achieved with the 3D evaporator during a long-term treatment of BPA-containing seawater under 1-sun irradiation. This work demonstrates efficient purification of seawater/wastewater with both metal ions and organic pollutants by simultaneous solar-thermal evaporation of water and catalytic degradation of organic pollutants.

A Review on Pulsed Laser Fabrication of Nanomaterials in Liquids for (Photo)catalytic Degradation of Organic Pollutants in the Water System.

The water pollution caused by the release of organic pollutants has attracted remarkable attention, and solutions for wastewater treatment are being developed. In particular, the photocatalytic removal of organic pollutants in water systems is a promising strategy to realize the self-cleaning of ecosystems under solar light irradiation. However, at present the semiconductor-based nanocatalysts can barely satisfy the industrial requirements because their wide bandgaps restrict the effective absorption of solar light, which needs an energy band modification to boost the visible light harvesting via surface engineering. As an innovative approach, pulsed laser heating in liquids has been utilized to fabricate the nanomaterials in catalysis; it demonstrates multi-controllable features, such as size, morphology, crystal structure, and even optical or electrical properties, with which photocatalytic performances can be precisely optimized. In this review, focusing on the powerful heating effect of pulsed laser irradiation in liquids, the functional nanomaterials fabricated by laser technology and their applications in the catalytic degradation of various organic pollutants are summarized. This review not only highlights the innovative works of pulsed laser-prepared nanomaterials for organic pollutant removal in water systems, such as the photocatalytic degradation of organic dyes and the catalytic reduction of toxic nitrophenol and nitrobenzene, it also critically discusses the specific challenges and outlooks of this field, including the weakness of the produced yields and the relevant automatic strategies for massive production.

A swarm of helical photocatalysts with controlled catalytic inhibition and acceleration by magneto-optical stimuli

Highly persistent and toxic organic pollutants increasingly accumulate in freshwater resources, exacerbating the human water scarcity crisis. Developing novel microrobots with high catalytic performance, high mobility, and recycling capability integrated to harness energy from the surrounding environment to degrade pollutants effectively remains a challenge. Here, we report a kind of Spirulina (SP)-based magnetic photocatalytic microrobots with a substantially decreased band gap than that of pure photocatalysts, facilitating the generation of stable holes and electrons. Under sunlight irradiation, the degradation rate of rhodamine B (RhB) by the microrobots could be increased by 7.85 times compared with that of pure BiOCl, indicating its excellent photocatalytic performance. In addition, the microrobots can swarm in a highly controllable manner to the targeted regions and perform selective catalytic degradation of organic pollutants in specific areas by coupling effect of light and magnetic field. Importantly, the catalytic capability of the swarming microrobots can be activated by light stimulus whereas inhibited by magneto-optical stimuli, with a rate constant 2.15 times lower than that of pure light stimulation. The biohybrid and magneto-optical responsive microrobots offer a potential platform for selective pollutants catalysis at assigned regions in wastewater treatment plants.

A sustainable solution for organic pollutant degradation: Novel polyethersulfone/carbon cloth/FeOCl composite membranes with electric field-assisted persulfate activation

Sulfate radical-based advanced oxidation processes (SR-AOP) and ultrafiltration (UF) membranes have demonstrated effectiveness in treating wastewater. This investigation illuminated a pioneering two-stage procedure for fabricating polyethersulfone/carbon cloth/FeOCl (PES/CC/FeOCl) composite catalytic membranes, exhibiting proficiency in persulfate activation. Evidenced by their distinctively high degradation rates and superior stability, these innovative composite membranes efficaciously obviate tetracycline (TC), showcasing a striking TC degradation rate, with an unparalleled removal ratio peaking at 93% under applied electrical fields. The process underlying persulfate activation and TC degradation was meticulously explored through electron paramagnetic resonance (EPR) and quenching trials. These evaluations unveil that hydroxyl radicals (•OH) and sulfate radicals (SO4•−) primarily drive the eradication of diminutive organic molecules. Subsequent studies emphasized the noteworthy rejection ratio of the PES/CC/FeOCl composite membranes (90%) for sodium alginate (SA), further revealing their exceptional on-line cleansing efficiency in an electrofiltration-associated in-situ oxidation system. In essence, this study proposed a novel approach for the synthesis of composite membranes adept at the catalytic degradation of organic pollutants. This paradigm-shifting research imparted a unique lens to perceive the integration of membrane separation technology, enriching the domain of advanced wastewater treatment strategies.

Co nanoparticles anchored N, B, F codoped carbon as an efficient peroxymonosulfate activator for rapid catalytic degradation of organic pollutants

Rational design and exploration of low-cost and robust carbocatalysts with multiple active sites for peroxymonosulfate (PMS) activation towards wastewater purification is challenging. Herein, Co nanoparticles anchored N, B, F-codoped porous carbon (Co@NBFOC) was synthesized and characterized thoroughly, which displayed superior PMS activation ability due to the synergy of multiple active sites. The Co@NBFOC-3/PMS system possessed excellent methylene blue (MB) oxidation capacity over a wide initial pH applicability (4-10) and showed high tolerance for Cl−, NO3−, SO42− and humic acid, while CO32−, HCO3− and HPO42− displayed a considerable inhibiting effect on it. Moreover, the Co@NBFOC-3/PMS system could afford acceptable MB degradation performance in different water matrix and universal applicability in eliminating a variety of organic pollutants. Both free radical pathway and nonradical pathway collectively contributed to MB degradation based on scavenging experiments, EPR measurements and electrochemical analyses. Particularly, ·O2−, 1O2, surface-bonded radicals (·SO4−ads and ·OHads) and catalyst mediated electron transfer were the major contributors, followed by ·SO4−free. Metallic Co, pyridinic-N moieties, graphitic-N moieties, BCO2 moieties, CO groups, the carbon atoms adjacent to graphitic-N, defects and ionic CF moieties on Co@NBFOC-3 surfaces corporately contributed to PMS activation. The main degradation intermediates were analyzed by HPLC-MS and the possible MB degradation pathways were proposed. This work not only improves the fundamental understanding of active sites in multi-heteroatom doped carbocatalysts, but also provides some guidance for future development of high-efficient carbon-based catalysts in PMS-based advanced oxidation processes.

Biochar/layered double hydroxides composites as catalysts for treatment of organic wastewater by advanced oxidation processes: A review

Heterogeneous advanced oxidation process has been widely studied as an effective method for removing organic pollutants in wastewater, but the development of efficient catalysts is still challenging. This review summaries the present status of researches on biochar/layered double hydroxides composites (BLDHCs) as catalysts for treatment of organic wastewater. The synthesis methods of layered double hydroxides, the characterizations of BLDHCs, the impacts of process factors influencing catalytic performance, and research advances in various advanced oxidation processes are discussed in this work. The integration of layered double hydroxides and biochar provides synthetic effects for improving pollutant removal. The enhanced pollutant degradation in heterogeneous Fenton, sulfate radical-based, sono-assisted, and photo-assisted processes using BLDHCs have been verified. Pollutant degradation in heterogeneous advanced oxidation processes using BLDHCs is influenced by process factors such as catalyst dosage, oxidant addition, solution pH, reaction time, temperature, and co-existing substances. BLDHCs are promising catalysts due to the unique features including easy preparation, distinct structure, adjustable metal ions, and high stability. Currently, catalytic degradation of organic pollutants using BLDHCs is still in its infancy. More researches should be conducted on the controllable synthesis of BLDHCs, the in-depth understanding of catalytic mechanism, the improvement of catalytic performance, and large-scale application of treating real wastewater.

Triboelectrification Catalytic Degradation of Organic Pollutants in Water Environment

With the rapid development of industrialization, more and more organic pollutants are entering the water environment, rendering the treatment of organic pollutants a key issue in protecting it. Therefore, finding a convenient and effective method for degrading organic pollutants in water is of great importance. Triboelectrification is known as the process of charge transfer during the friction process. It is always accompanied by the energy level transition of electrons or holes, making it a potential method for catalytic degradation, which we refer to as triboelectrification catalysis. In this study, a set of experimental equipment was developed. The device is composed of a mechanical system, a control system, and a measurement system that can realize the quantitative measurement of the triboelectrification catalysis under different friction pairs, different loads, and different contact frequencies. Using the developed device, we observed stable triboelectrification catalytic degradation. This study performed triboelectrification catalytic experiments on various organic compounds including methyl orange, rhodamine, and tetracycline. The results revealed that these three organic compounds were degraded by 39%, 15%, and 20%, respectively, within three hours of being under the influence of triboelectrification catalysis. Subsequently, this study conducted triboelectrification catalytic experiments using materials with different triboelectric capacities. This study found that the triboelectric capacity significantly impacted the triboelectrification catalytic degradation rate, providing further evidence for the mechanism of triboelectrification catalysis. Additionally, this study found that SiO2 and Al2O3, which also utilize electrons as the primary carrier for triboelectrification, are capable of catalyzing the degradation of a methyl orange solution. Therefore, this study suggests that the triboelectrification catalysis is a versatile and widely applicable method for treating organic pollutants in water. With a broad range of catalyst sources and the ability to effectively degrade various organic pollutants, it shows promise as a solution for the problem of water pollution.

Efficient degradation of norfloxacin using a novel biochar-supported CuO/Fe3O4 combined with peroxydisulfate: Insights into enhanced contribution of nonradical pathway

Nonradical persulfate oxidation techniques have evolved as a new contaminated water treatment approach due to its great tolerance to water matrixes. The catalysts of CuO-based composites have received much attention in that aside from SO4•−/•OH radicals, the nonradicals of singlet oxygen (1O2) can be also generated during persulfate activation via CuO. However, the issues regarding particles aggregation and metal leaching from the catalysts during the decontamination process remain to be addressed, which could have a remarkable impact on the catalytic degradation of organic pollutants. Accordingly in the present study, a novel biochar-supported bimetallic Fe3O4–CuO catalyst (CuFeBC) was facilely developed to activate peroxodisulfate (PDS) for the degradation of norfloxacin (NOR) in aqueous solution. The results showed CuFeBC has a superior stability against metal ions Cu/Fe leaching, and NOR (30 mg L−1) was degraded at 94.5% within 180 min in the presence of CuFeBC (0.5 g L−1) and PDS (6 mM) in pH 8.5. The scavenging of reactive oxygen species and electron spin resonance analysis revealed that 1O2 dominated the degradation of NOR. Compared with pristine CuO–Fe3O4, the interaction between biochar substrate and metal particles could significantly enhance the contribution of the nonradical pathway to NOR degradation from 49.6% to 84.7%. Biochar substrate could efficiently reduce the leaching of metal species from the catalyst, thereby maintaining excellent catalytic activity and lasting reusability of the catalyst. These findings could enlighten new insights into fine-tuning radical/nonradical processes from CuO-based catalysts for the efficient remediation of organic contaminants in polluted water.

Synthesis of nanomagnetite/copper oxide/potassium carrageenan nanocomposite for the adsorption and Photo-Fenton degradation of Safranin-O: kinetic and thermodynamic studies

In the current study, a novel nanomaterial called nanomagnetite/copper oxide/potassium carrageenan nanocomposite (MKCO) was fabricated to include Fenton (nanomagnetite, NM) and Fenton-like reagent (copper oxide nanoparticles, NCO) in a matrix of potassium carrageenan biopolymer. The prepared solid materials were characterized by different physicochemical techniques, such as TGA, N2 adsorption/desorption, SEM, TEM, XRD, DRS, pHPZC, and FTIR. The prepared MKCO showed unique properties like higher specific surface area of 652.50 m2/g, pore radius of 1.19 nm, pHPZC equals 7.80, and the presence of different surface chemical functional groups. Under various application conditions, comparative experiments between Safranin-O dye (SO) adsorption and Photo-Fenton catalytic degradation were conducted. After 24 h, MKCO had a maximum adsorption capacity of 384.61 mg/g at 42 °C, while the Photo-Fenton oxidation process took only 10 min to totally decompose 93% of SO at 21 °C. Based on the higher values of correlation coefficients, Langmuir’s adsorption model is the best-fitted adsorption model for SO onto all the prepared solid materials. Studies on SO adsorption’s kinetics and thermodynamics show that it is physisorption and that it operates according to endothermic, spontaneous, and PFO model processes. While, PFO, endothermic, and non-spontaneous processes are satisfied by the catalytic decomposition of SO. After five application cycles, MKCO demonstrated good catalyst reusability with a 3.4% decrease in degrading efficiency. For lower contaminant concentrations and shorter application times, Photo-Fenton catalytic degradation of organic pollutants is more effective than adsorption.Graphical abstractFenton and Photo-Fenton degradation of Safranin-O

Enhanced activation of H2O2 by bimetallic Cu2SnS3: A new insight for Cu (II)/Cu (I) redox cycle promotion

HypothesisDespite that the development of Cu2SnS3 (CTS) catalyst has attracted increasing interests, few study has reported to investigate its heterogeneous catalytic degradation of organic pollutants in a Fenton-like process. Furthermore, the influence of Sn components towards Cu (II)/Cu (I) redox cycling in CTS catalytic systems remains a fascinating research. ExperimentsIn this work, a series of CTS catalysts with controlled crystalline phases were prepared via a microwave-assisted pathway and applied in the H2O2 activation for phenol degradation. The efficiency of phenol degradation in CTS-1/H2O2 system (CTS-1: the molar ratio of Sn (copper acetate) and Cu (tin dichloride) is determined to be Sn:Cu = 1:1) was systematically investigated by controlling various reaction parameters including H2O2 dosage, initial pH and reaction temperature. We discovered that Cu2SnS3 exhibited superior catalytic activity to the contrast monometallic Cu or Sn sulfides and Cu (I) acted as the dominant active sites. The higher Cu (I) proportions conduce to the higher catalytic activities of CTS catalysts. Quenching experiments and electron paramagnetic resonance (EPR) further proved that the activation of H2O2 by CTS catalyst produces reactive oxygen species (ROS) and subsequently leads to degradation of the contaminants. A reasonable mechanism of enhanced H2O2 activation in Fenton-like reaction of CTS/H2O2 system was proposed for phenol degradation by investigating the roles of copper, tin and sulfur species. FindingsThe developed CTS acted as a promising catalyst in Fenton-like oxidation progress for phenol degradation. Importantly, the copper and tin species contribute to a synergetic effect for the promotion of Cu (II)/Cu (I) redox cycle, which thus enhanced the activation of H2O2. Our work may offer new insight on the facilitation of Cu (II)/Cu (I) redox cycle in Cu-based Fenton-like catalytic systems.

Preparation of Nano Ag Loaded Wood Filter Material and Its Catalytic Degradation of Dyes

Using porous light wood as raw material, Ag/wood composite filter material was prepared by loading metal Ag nano catalyst in wood matrix by in-situ reduction of silver ammonia solution. The catalytic degradation of organic pollutants in dye wastewater was realized by using the characteristics of high fluid transmission efficiency of wood and catalytic activity of silver nanoparticles. The morphology and structure of the material were characterized by scanning electron microscope, transmission electron microscope and X-ray diffraction, and the catalytic degradation of organic dye methylene blue by nano Ag loaded wood filter material was investigated. The results show that the prepared Ag/wood composite filter material retains the pore structure of wood, Ag nanoparticles are successfully loaded on the inner wall of the catheter and evenly distributed, and the particle size range is 5 nm-20 nm; The silver nanoparticles on the inner wall of the wood duct have good catalytic activity, and the wood filter material can effectively catalyze the degradation of methylene blue in water. Its degradation efficiency and water flux are closely related to the thickness of the filter material; The catalytic degradation efficiency of methylene blue by 6 mm thick filter material driven by gravity is 94.03%, and the water flux is up to 2600 L/(M2•h), which realizes the optimization of dye degradation efficiency and water flux. Nano Ag loaded wood filter material has the advantages of simple preparation process, low cost and large-scale. It has a good application prospect in the field of dye wastewater treatment.