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[Display omitted] • Function of oxalic acid assisted Fenton-like reaction in composting carbon conservation was verified. • The concentration of ·OH was increased via using Fenton-like reagent during composting. • Fenton-like reagent addition facilitated organic matter decomposition and humification. • The degree of aromatization was facilitated by Fenton-like reagent monitored by spectral determinations. • Fenton-like treatment also facilitated microbial activity for improving humification. To illustrate the role and mechanism of using oxalic acid (OA) and Fenton reagent to enhance carbon transformation and humification in the co-composting of swine manure and corn straw, four different treatments, SW1 (Control), SW2 (Fenton reagent), SW3 (10 % OA), and SW4 (Fenton reagent + 10 % OA) were set up for an 80-day pilot-scale composting. Compared with the Fenton pretreatment, the contents of Fe (II) and hydroxyl radicals (·OH) in the SW4 treatment increased by 20.25 %-54.55 % and 6.39 %-71.00 %, respectively. This confirmed the role of OA in protecting Fe (II) and maintaining the generation of ·OH during the composting. Compared with Control, Fenton-like reagent amendment facilitated decomposition of dissolved organic carbon and total organic matter by 20.53 % and 25.37 %, respectively, which led to a higher content of humic substances (141.81 mg/g) and a higher degree of polymerization (3.51) in SW4. Among all, the dissolved organic carbon in the compost substrate of SW4 treatment showed the highest level of aromatization and more refractory organic matter decomposition. The compact microbial co-occurrence network analysis exhibited the high-metabolic activity in Fenton-like treatment (SW4). Therefore, the probable mechanism of humification facilitation by Fenton-like reagent amendment in co-composting could be controlled by several processes: 1) generation of ·OH for facilitating the decomposition of organic matter, 2) disintegration of refractory lignocellulose substances by promoting the lignin pathway of humification, and 3) increasing the quantity and activity of microbes (i.e., Proteobacteria, Actinobacteriota, Chloroflexi, Ascomycota and Basidiomycota) involved in humification. This study provided a profound understanding of Fenton-like reagent amendments in co-composting of agricultural solid wastes and proposes a solution for enhancing the humification degree of compost products for agricultural use. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mg-modified biochar exhibited a high P adsorption capacity (∼248 mg g−1). • Goethite was more effective than hematite in reducing P transport in columns. • Coexistence of biochar and goethite increased available retention sites of P. • Citric acid and oxalic acid achieved release of P retained in columns. The practical effects of biochar on soil phosphate (P) transport are significantly affected by P adsorption capacity of biochar itself and its interaction process with iron oxides. Here, the ability of pyrolysis to shape P adsorption capacity of biochar was investigated, while the interaction of biochar and iron oxides on P transport was explored with quartz sand columns and numerical modeling. Adsorption experiments showed that pyrolysis increased P adsorption capacity of Mg-modified biochar (∼248 mg g−1) through enriching surface morphology and pore structures, optimizing composition of functional groups, and forming MgO crystals. It also caused that P adsorption at MgBC-700°C was mainly controlled by surface precipitation, electrostatic attraction and pore interception. Simultaneously, the desorption of P was sensitive to pH changes and with low-stability. Transport experiments showed that iron oxides reduced P transport, shown to be goethite > hematite (P leaching: 69.59 % vs 98.29 %). Further, MgBC-700°C continued to decrease P transport from 75.56 % to 31.50 %, and the effect of goethite was more effective, with ligand reaction playing an important role. This process was influenced by cation types (Ca2+ and K+), ionic strength (1 mM and 50 mM), and pH (5, 7 and 9) through changing available retention sites of columns. Furthermore, since P adsorption mechanisms were different in the presence of MgBC-700°C and goethite than MgBC-700°C only, the changes of pH could no longer cause the release of P, but surprisingly, citric acid and oxalic acid could activate and slowly release the retained P via chelation, ligand exchange, and solubilization, which suggested that MgBC-700°C, as an environmentally-friendly P adsorption and release material, has great potential in reducing P loss and facilitating P utilization. [ABSTRACT FROM AUTHOR]

• Developed oxalic acid (OA) chelated electrochemical (EF) released Fe2+ activated CaO 2 pre-conditioned sludge process. • EF-CaO 2 /OA effectively enhanced sludge dewaterability at neutral pH. • EF-CaO 2 /OA provides durable and effective oxidizing power. • End-of-conditioned sludge was still pH-neutral. • Altered protein secondary structure transforms sludge from hydrophilic to hydrophobic. In this study, we investigated the efficiency of activation of CaO 2 by oxalic acid (OA) chelated with electrochemically (EF)-released Fe2+ (EF-CaO 2 /OA) in improving the performance of sludge dewatering under neutral conditions. We also explored the mechanism of OA-reinforcement of EF-CaO 2 in enhancing the performance of wastewater-activated sludge dewatering by investigating the water content (Wc), specific resistance to filtration (SRF), pH, bound water content, extracellular polymers in the sludge, the secondary structure of proteins, the soluble ferric ions, and the morphology of the sludge. The EF-CaO 2 /OA process was better than the EF-CaO 2 process in terms of sludge dewatering. OA introduction significantly inhibited the increase of solution pH, which in turn promoted CaO 2 dissolution and persistent H 2 O 2 generation. The persistent oxidative reaction contributed to the degradation of hydrophilic protein fractions in EPS and the reduction of the proportion of hydrophilic structures in the secondary structure of proteins, which in turn improved the hydrophobicity of the sludge. The changing profile of DNA content in EPS proved that EF-CaO 2 /OA led to the damage of more sludge cells. It suggested that OA enhanced the oxidizing efficacy of EF-CaO 2 , which in turn promoted the release of bound water from more sludge cells. Moreover, OA significantly increased the amount of dissolved iron in solution by chelating the electrochemically released iron, which contributed to the stabilization of the oxidation reaction. Under the optimal conditions, sludge Wc and SRF treated by EF-CaO 2 /OA were reduced by 30.1% and 96.9%, respectively, and the dewatered sludge cake remained neutral. In conclusion, EF-CaO 2 /OA may be an efficient and feasible technique for deep sludge dewatering. [ABSTRACT FROM AUTHOR]

• Pro@MPDA-BIZ@β-CD was prepared by encapsulating Pro within polybdopamine carrier modified by benzimidazole and cyclodextrin. • Nano-pesticide with pH and near-infrared dual response, used in different administration modes. • Pro@MPDA-BIZ@β-CD showed excellent antifungal effects against Sclerotinia sclerotiorum. • Pro@MPDA-BIZ@β-CD showed better biological safety and wettability. Considering the microenvironment of pathogens, the use of highly biocompatible antibacterial materials loaded with fungicides and the on-demand delivery of fungicides through controlled release can effectively improve the biocompatibility and antibacterial effect of existing fungicides. In this study, we used mesoporous poly-dopamine nanoparticles (MPDA NPs) as a carrier, prochloraz (Pro) as a loading agent, and benzimidazole (BIZ) and β-cyclodextrin (β-CD) complex as a blocking agent to prepare the on-demand delivery nano-pesticides Pro@MPDA-BIZ@β-CD (hereinafter abbreviated as PMBD), which can be administered at different stages. Sclerotinia sclerotiorum secretes oxalic acid factor to create an acidic microenvironment, and the nano-system quickly releases fungicide Pro into the mycelium. MPDA materials also responds to oxalic acid to jointly reduce the pathogenicity of Sclerotinia sclerotiorum , effectively inhibiting the growth of Sclerotinia sclerotiorum , and realizing the treatment of Sclerotinia sclerotiorum infection. On the other hand, when plants are not infected with Sclerotinia sclerotiorum , MPDA with a photothermal effect triggers the release of fungicides under the irradiation of near-infrared light, thus preventing Sclerotinia sclerotiorum infection. The in vitro release experiment showed that the cumulative release of Pro under low pH and near-infrared light irradiation was 2.68 times and 2.04 times higher than that under neutral and no light conditions, respectively. On the other hand, the rich functional groups on MPDA-BIZ@β-CD(hereinafter abbreviated as MBD) gave the system good wettability, and the contact angles of MBD on Chinese cabbage and tomato leaves were reduced by 14.85° and 41.54°, respectively, which enhanced its resistance to rainwater erosion and prevented the fungicides from being lost to the environment. In addition, bio-safety experiments have shown that PMBD has good biocompatibility to plant germination and soil microorganisms. [ABSTRACT FROM AUTHOR]

• This work proposes a new idea of recycling spent LIBs. • Recycled LIBs as catalysts for NO x removal. • Oxalic acid as leaching and precipitating agent. • The use of oxalic acid facilitates the creation of pore structures. • Catalyst achieves nearly 100 % NO x conversion at 110 ∼ 230 °C. The wide application of lithium-ion batteries (LIBs) for electric vehicles forebodes the decommissioning tide of spent LIBs. Therefore, recycling valuable element from spent LIBs are becoming urgent to minimize the impact on the environment and supply chain of battery manufacturers. In this work, we propose to extract valuable elements from the cathode materials of spent ternary lithium-ion batteries and synthesize NiCoMnO x catalysts for low-temperature NH 3 selective catalyst reduction (NH 3 -SCR) reactions. The oxalic acid is used as a precipitant and reducing agent and prepared as NiCoMnO x catalyst by hydrothermal process and heat treatment. The as-prepared catalyst presents a porous fluffy foam structure with abundant oxygen defects, ensuring sufficient catalytic active sites. As a result, the NiCoMnO x catalyst exhibits optimal catalytic activity with over 90% NO x conversion in the temperature range of 110 ∼ 230 °C, which is wider than the temperature range of 155 ∼ 210 °C for the catalysts prepared from metal salts. Meanwhile, the NiCoMnO x catalyst also shows better catalytic stability and resistance to H 2 O and SO 2. This work provides a promising strategy to recycle spent LIBs to low-temperature NH 3 -SCR catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cost-effective and green process is proposed to recover spent Co-poor LIBs. • Oxalic acid exhibits a quadruple role in the recycling of spent Co-poor LIBs. • Over 95.0% of Li is selectively recovered with low consumption and discharge. • Residue is non-hazardously converted into high-performance porous function material. • This process is available to multiple spent Co-poor LIBs resource recycling. As more spent ternary Co-poor lithium-ion batteries (LIBs) appear, traditional recycling processes could be challenged because of the reduced revenues caused by complex separation-purification processes. In this study, a cost-effective and environmentally friendly hydrometallurgical process assisted by the versatile oxalic acid is proposed for recycling spent ternary Co-poor LIBs. In this process, lithium is selectively leached without reductants because of the differences in oxalate solubility. Its selectivity is up to 95.0 %, which is 2.5 and 9.5 times that of formic acid and phosphoric acid/hydrogen peroxide selective leaching systems, respectively. The obtained lixivium can be reused in the leaching step to realize the enrichment of Li+, thereby reducing the discharge of wastewater and energy consumption required to recover Li+ in the form of Li 2 CO 3. Additionally, the generated residue is non-hazardously converted into a porous functional material, whose performance in environmental treatment (i.e., emerging contaminant removal) and energy storage (i.e., supercapacitors) is superior to that of previously reported multifunctional materials. More importantly, this simplified process exhibits attractive profits (approximately $2,161/t) and is applicable to recycling multiple spent ternary Co-poor LIBs (e.g., NCM523 and NCM811). This study provides a promising route to sustainably recycle spent ternary Co-poor LIBs, probably contributing to developing spent ternary LIBs resource recycling process conformed to the goal of "carbon neutrality." [ABSTRACT FROM AUTHOR]

[Display omitted] • Electro-oxidation of N-heterocycles produces N 2 , N H 3 / N H 4 + , N O 3 - , C O and C O 2. • N H 3 / N H 4 + and an apparent N 2 yield correlate linearly with carbon removal. • Both apparent N 2 and N O 3 - form directly from organic intermediates rather than N H 3 / N H 4 +. • Higher concentrations of parent compounds promote a higher apparent N 2 selectivity. • N O 3 - dominates when oxidation of carbon is mass transfer-limited or at basic pH. We report for the first time the carbon and nitrogen product distribution during the electrochemical oxidation (EO) of pyrazine and related N-heterocyclic compounds (NHCs) present in the hard-to-treat wastewater from a biofuel production process. The experimental study was carried out using a boron-doped diamond anode. Identified and quantified intermediate products included oxamic acid, formamide, oxalic acid, and formic acid. Analysis of the C and N yields as a function of the extent of carbon removal reveals the influence of the current- and mass transfer-control operating regimes on product distribution. Carbon monoxide, which was detected among the gaseous products, suggests a possible decarbonylation pathway in the current-controlled regime. An apparent nitrogen gas and ammonium yields correlated linearly with the carbon removal, while nitrate yields significantly increased in the mass transfer-controlled regime. Nitrate and apparent nitrogen gas appear to form directly from organic nitrogen intermediates, rather than from the ammonium that also forms in the process. The research gives new insights into the NHCs degradation pathways, product distribution, and final water composition as a function of operating regime in the EO of recalcitrant wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eletrospun Fe N C fibers were used for an alkaline hydrazine fuel cell (AHFC). • Steam activation creates a hierarchical mesopore structure for oxygen reduction. • Steam activation raised the AHFC power density from 323 to 625 mW cm−2. • Fe 3 O 4 leaching by oxalic acid elevates the mesopore volume and hydrophobicity. • Oxalic acid leaching achieved 1240 mW cm−2 due to increased triple-phase boundary. In alkaline hydrazine fuel cells (AHFCs), the rapid kinetics of hydrazine oxidation contribute to their superior power density compared to other liquid fuel cells. However, the optimization of oxygen reduction reaction (ORR) electrodes in AHFCs has received limited attention, despite the potential importance of ORR as a rate-determining step. The wettability and pore structure of ORR catalysts are critical factors in facilitating reactant supply (O 2 and H 2 O) and improving catalyst utilization. In this study, we synthesized a hierarchical pore structure in a FeNC catalyst by excess iron incorporation and steam activation, and adjusted its water/oxygen gas contact property by oxalic acid treatment. The modified catalyst exhibited improved wettability and optimized triple-phase boundaries. Remarkably, utilizing a 25 cm2 electrode size and non-noble electrocatalysts, the resulting AHFC achieved a significant power density improvement from 630 to 1240 mW cm−2, setting a new record for AHFCs. This research highlights the importance of pore structure and surface engineering, including the role of excess iron, in enhancing the performance of ORR electrodes in AHFCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxalic acid enhanced the SMX removal by heterogeneous V 2 O 3 /percarbonate process. • •OH was the main precursor of CO 3 •- and O 2 •-. • Intramolecular electron transfer process was involved in the generation of •OH. • Oxalic acid restricted the conversion of •OH to CO 3 •- and O 2 •-. Sewage disposal technology in advanced oxidation processes (AOPs) should be enriched for providing more options for practical application. Herein, degradative and mechanistic investigation of heterogeneous V 2 O 3 -activated sodium percarbonate (SPC) process was implemented in the presence of oxalic acid (OA). The experimental results indicated a strong dependency of sulfamethoxazole (SMX) degradation on SPC dosage and a wide adaptability to the ambient pH in V 2 O 3 /SPC/OA system. Efficient removal of SMX in water reached 93.4 % within 10 min at the initial presence of 0.1 g/L V 2 O 3 and 2 mM SPC. Mechanistic experiments revealed that •OH played an indispensable role in SMX degradation, which partially dominated the degradation process and partially was the main precursor of CO 3 •- and O 2 •-. Moreover, except for the single electron transfer from low-valence state of vanadium (V) species to SPC, the intramolecular electron transfer process from –OOH ligand of V complex to hydrogen peroxide (H 2 O 2) also participated in the generation of •OH. Additionally, the introduction of OA could provide a complex, transient acidic and reductive condition for facilitating the SMX removal process. On the other hand, the addition of OA restricted the conversion of •OH to CO 3 •- and O 2 •-. Zeolite was employed to absorb the V species in the aqueous solution after the reaction and the residual vanadium concentrations were <2 mg/L. The existence of HPO 4 2-, CO 3 2– and humic acid exerted severe inhibition on the decontamination of SMX, and F- and NO 3 – exerted slight suppression, whereas the existence of Cl- and SO 4 2- did not show conspicuous impairment. This work filled the gap of decontamination performance of SMX in vanadium based heterogenous SPC system and deepened the understanding of the application of reductant. [ABSTRACT FROM AUTHOR]

• MgO@CeO 2 -MnO x weakens competitive adsorption of SO 2 and NO x. • Effect of different operating conditions on adsorption performance. • The important role of Mn/Ce element. • Surface oxidation and adsorption. Magnesium oxide (MgO) with different morphologies was prepared by oxalic acid sol-gel method and the MgO were used to prepare three different kinds of adsorbents for simultaneous SO 2 and NO x removal from coal-fired flue gas. It was found that the core-shell coated adsorption material MgO@CeO 2 -MnO x prepared from MgO formed by calcination of magnesium oxalate at 650 ℃ had the best performance. The MgO@CeO 2 -MnO x exhibited an adsorption breakthrough time up to 50 min and dynamic adsorption capacity of 0.3507 mmol/g and 0.1407 mmol/g for SO 2 and NO x respectively. This is better than any other composite material. The N 2 adsorption-desorption isotherms result showed that core-shell structure material possessed the largest specific surface area, which could be its basic advantage for efficient adsorption. According to different operating conditions tests, it was found that the adsorption of SO 2 and NO x by the adsorbent was dominated by chemisorption. Therefore, the surface metal material (MnO x , CeO 2) played an important role in the adsorption process. According to FTIR and DRIFTS analysis, it was observed that the SO 2 and NO were oxidized by hydroxyl groups on the absorbent surface and the oxidation was further aggravated by the presence of Mn4+, Mn3+, Ce3+and Ce4+. Core-shell materials successfully prepared can reduce or weaken the adsorption competition between SO 2 and NO x in three aspects: 1. The surface oxidation ability is strengthened and it is easy to adsorb the two substances, which makes the metal oxides on the shell surface interact fully with the adsorbents; 2. More and more effective adsorption sites are provided; 3. The adsorbent provides greater specific surface area and appropriate pore size. [ABSTRACT FROM AUTHOR]

Highlights • Porous NiCo 2 O 4 /NiO/Co 3 O 4 nanoflowers (NCNs) are prepared by adding oxalic acid. • NCNs-0.1 possess optimal distribution of micro-mesopores. • NCNs-0.1 electrodes deliver an enhanced specific capacitance of 1693F g−1. • 88% capacitance can be retained after 6000 cycles. • Excellent energy densities of 43.02 Wh kg−1 and power densities of 820.29 W kg−1. Abstract The rational design of micro-mesopores is a hugely challenging for porous metal-based nanomaterials. Here oxalic acid (H 2 C 2 O 4) as control agent is proposed for the first time to prepare 3D optimal micro-mesoporous NiCo 2 O 4 /NiO/Co 3 O 4 nanoflowers (NCNs). Theoretical and experimental analyses demonstrate NCNs-0.1 which are prepared by adding 0.1 g H 2 C 2 O 4 possess optimal distribution of micro-mesopores. The optimal structure creates abundant active sites and fluent ionic channels. Beneficially, NCNs-0.1 electrodes deliver an enhanced specific capacitance of 1693F g−1 at 1 A g−1 and outstanding cyclic stability (88% capacitance retention after 6000 cycles). Further, the assembled NCNs-0.1//AC capacitor achieves excellent energy densities of 43.02 Wh kg−1 at power densities of 820.29 W kg−1. The current NCNs-0.1 confirms a practicable method to optimize the electrochemical performances of supercapacitors by utilizing H 2 C 2 O 4 to construct 3D optimal micro-mesoporous nanoflower architectures. [ABSTRACT FROM AUTHOR]

[Display omitted] • A rapid and efficient pretreatment method was proposed to improve enzymolysis efficiency and biohydrogen production. • 95% cellulose retention and 81.3% delignification was achieved by molten oxalic acid dihydrate pretreatment. • 85 % enzymolysis conversion and 114.04 mL H 2 /g TS can be obtained at 110 °C within 5 min treatment. Biohydrogen production from lignocellulose presents an enduring challenge due to the tough, rigid, and complex structure that endows the lignocellulose with high resistance to biodegradation. In the present work, a rapid and effective pretreatment method employing molten oxalic acid dihydrate (OAD) was proposed to enhance enzymatic saccharification for biohydrogen production through efficient coextraction of wheat straw. The molten OAD pretreatment at 110 °C achieves a 95 % cellulose retention, 95 % hemicellulose removal, and 81.3 % delignification within 5 min. Furthermore, an 85 % enzymolysis conversion rate and 114.04 mL/g total solids (TS) fermentative hydrogen yield can be obtained. The OAD pretreatment enhanced the feasibility of biomass refining and paves the way for a novel, fast and high-efficiency pretreatment method for advancing the productivity stage toward biohydrogen production from lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn-CSM is of high catalytic activity, stability and recyclable capability for HCO process. • Mn-CSM HCO is effective for oxalate removal and coal gasification wastewater treatment. • The introduction of SiO 2 on the carbon fibers promotes the distribution of fluid flow field. • Mn-CSM have a higher removal for HIS due to higher hydrophilicity brought up by SiO 2. Heterogeneous catalytic ozonation (HCO) is a promising technology for advanced wastewater treatment, and developing catalysts with both high catalytic activity and easy recycling capability is challenging but essential. In this work, easily separable Mn loaded carbon–silica-membrane (Mn-CSM) was synthesized by electrospinning and Mn-CSM based packed bed reactor was constructed for catalytic ozonation, achieving excellent catalytic performance for refractory organic degradation. Mn-CSM exhibited a lamellar structure with a thickness of several hundred micrometers and was centimeter-sized in the other two dimensions, which make it easy to be separated in wastewater treatment. At the microscopic scale, Mn-CSM was composed of highly connected nanofibers, which provided large specific surface area for the exposure of active sites. In oxalic acid (OA) degradation and coal gasification wastewater advanced treatment, Mn-CSM demonstrated superior catalytic ozonation performance. After 60 min, 93% of OA was degraded in Mn-CSM based HCO process, and the effluent COD of coal gasification wastewater decreased from 105 mg L−1 to 42 mg L−1. Reactive oxygen species in aqueous solution and on catalyst surface contributed to the organic degradation. The introduction of SiO 2 nanoparticles in Mn-CSM can not only enhance its catalytic stability, but also improve fluid flow field distribution. Furthermore, the presence of SiO 2 increased the hydrophilicity of Mn-CSM and a better removal of hydrophilic substances (HIS) was achieved in Mn-CSM based HCO. This study highlights a Mn-CSM ozone catalyst with high catalytic activity and easy recycling capability and a Mn-CSM based catalytic ozonation process, which is promising for the degradation of refractory organics in wastewater. [ABSTRACT FROM AUTHOR]

• Shearing and synthesizing made starch into multiscale pyranose esters (MPE). • MPE locked ethanol in gel (MSE) through high-density hydroxyl and H-bonds donors. • Ethanol was only released under pressure to realize contact-killing bacteria of MSE. • MSE had good adhesion and could inhibit contact transmission of bacteria in public. • MSE reduced the ethanol dosage by 571 and 225 times more than EA and CEA in public. The large-scale spraying of disinfectants has little effect on cutting off the contact transmission of bacteria, triggering a series of economic burdens and environmental pollution in public places. Herein, a novel multiscale starch-based ethanol gel (MSE) was prepared by shearing cassava starch at different temperatures and subsequently esterifying with oxalic acid to obtain multiscale pyranose esters (MPE), which targeted ethanol in a specific location to release only when human touched. Strong hydrogen bonding and nanoscale voids made MSE locking ethanol, and the destruction of this hydrogen bonding by water and pressure also promoted ethanol release to fingers. In terms of this, fingers could be sterilized by pressing MSE, especially when the pressure force on MSE was greater than 2.263 N, more than 95.76% of E. coli and S. aureus on fingers are inactivated. Meanwhile, compared with pure ethanol disinfectants and commercial ethanol gel, MSE reduced the ethanol dosage by 571 times and 225 times when kept sterile for three days in the same public area. Excellent adhesion and biocompatibility of MSE indicate that novel ethanol gel can be exerted to suppress contact transmission of bacteria in a practical and harmless way. [ABSTRACT FROM AUTHOR]

[Display omitted] • The O-g-C 3 N 4 / artificial converter slag (OCN/artCS) were simply prepared. • artCS served as photocatalyst support for OCN growth due to Ca 2 Fe 2 O 5 existence. • OCN/artCS effectively converted biomass-derived sugars to lactic acid. • The heterojunction of OCN/Ca 2 Fe 2 O 5 -bearing artCS suppressed e--h+ recombination. The development of high performance, low-cost and resource-efficient photocatalysts with improved solar light harvesting capabilities can significantly enhance the practicability and viability of photocatalytic conversion of biomass-based substances to value-added chemicals. This work reports the construction of heterojunction between oxygen-doped graphitic carbon nitride and artificial steel converter slag (OCN/artCS) as efficient photocatalysts for conversion of biomass-derived monosaccharide to lactic acid under the simulated solar light. The OCN/artCS composites were facilely fabricated by the thermal polymerization of the mixtures of dicyanamide (DA) and oxalic acid (OA), which are precursors of OCN. The artCS acts as photocatalyst support for OCN to grow on its surface and can provide Ca 2 Fe 2 O 5 semiconductor to possibly form the OCN/Ca 2 Fe 2 O 5 -containing artCS heterojunction. Compared with pristine OCN, the OCN/artCS composites exhibited higher photocatalytic performance for selective production of lactic acid, possibly due to the effective separation of photogenerated charge carriers after creation of OCN/artCS heterojunction. At the optimal content of artCS in the composites, the OCN/5%artCS delivered 99% glucose conversion and 90% lactic acid yield within 60 min at 50 °C under the simulated sunlight irradiation. This work can be a platform for the efficient utilization of industrial solid wastes for production of high-performance photocatalysts, enabling their promising applications in photobiorefinery and other photocatalytic processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Fe2+/OA/PS system was efficient over a wide pH range. • Exogenous Fe2+ and Fe3+ dissolved from soil participated in PS activation. • CO 2 •- radicals contributed to the reduction of Fe3+/Fe3+-OA. • TCS degradation pathways were proposed in the Fe2+/OA/PS system. • Column experiments simulated TCS in-suit remediation in the Fe2+/OA/PS system. Triclosan (TCS) is a compound in pharmaceutical and personal care products (PPCPs) that preferentially accumulates in soil and may threaten human health. Iron-based persulfate activation processes (Fe-PAPs) are a promising technique in soil remediation but are limited by their narrow pH application range and resultant iron precipitation. In this study, oxalic acid (OA) was specifically introduced to improve the efficiency of Fe2+-activated persulfate (PS) processes for TCS degradation in soil. The complexation of OA and Fe2+ improved the total iron concentration in the Fe2+/OA/PS system and prevented iron precipitation. Fe-minerals in soil were also dissolved by OA, which participated in PS activation. The most appropriate proportion of Fe2+/OA/PS is 1:1:1, and approximately 85% of the TCS was degraded within 240 min compared with 45% in the Fe2+/PS system. SO 4 •- and 1O 2 played important roles on TCS oxidation, while O 2 •- and CO 2 •- mainly participated in the iron cycle. The weak stretch of Fe-O in OA containing treatments in ATR-FTIR measurements provided evidence that OA dissolved the Fe-minerals. The introduction of OA in the Fe2+/PS system in four different soils reduced the negative effect of soil organic matter on TCS degradation. Three types of intermediates including hydroxylation, cleavage of ether bonds and cyclization products, were identified by LC-Q-TOF-MS. Column experiments were used to study the feasibility of in situ chemical oxidation (ISCO) remediation of TCS in the Fe2+/OA/PS system. Our findings indicated the ability of OA to be used as a cheating agent in Fe-PAPs for TCS soil remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Supported Pd-catalyzed carbonylative synthesis of 2-aryl benzimidazoles. • Air/moisture stable, easy to handle and recyclable catalyst. • Oxalic acid as ex-situ green, economic and readily available CO and CO 2 source. • In-situ formed aryl carboxylic acid acts as catalyst for dehydrative cyclization. • Only catalytic amount of inorganic base (K 2 CO 3) is required. • Easy accessibility and affordability to starting materials. Herein, polystyrene supported palladium (Pd@PS) nanoparticles (NPs) catalyzed carbonylative synthesis of 2-aryl benzimidazoles from aryl iodides and aromatic diamines has been introduced. In-situ formed aryl carboxylic acid was revealed as a catalyst for dehydrative cyclization of secondary (2°) and tertiary (3°) amides formed via aminocarbonylation between aryl iodides and aromatic diamines. Herein, oxalic acid acts as carbon monoxide (CO) and carbon dioxide (CO 2) gases source plausibly leading to aminocarbonylation via CO gas as major pathway and carboxylation of aryl iodides via CO 2 as minor pathway. The Pd@PS catalyst was found to be easily separable, air/moisture stable and recyclable under the targeted reaction conditions. In addition, the present protocol requires only catalytic amount of inorganic base (K 2 CO 3) to achieve the highest yields of desired products. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was synthesized by two methods (Hummers and Brodie), N and S-doping of reduced graphene oxide (rGO) being achieved by thermal treatment. These materials were tested as ozonation catalysts, the N-doped (3.3 at.%) material prepared by Brodie’s method accomplishing complete removal of oxalic acid, while this compound is refractory to non-catalytic ozonation. Titanium dioxide (TiO 2 ) nanoparticles were then introduced as own catalytic phase and protection component to avoid the strong erosive effect of ozone over the carbon phase (GO, rGO, N- and S-doped rGO, obtained by both methods). Among the resulting set of eight TiO 2 -based composites, the highest catalytic activity in ozonation was obtained with the composite containing N-doped reduced graphene oxide derived from Hummers’ method (rGOT-H-N, k app  = 9.87 × 10 −3  min −1 ). This was attributed to the high content of oxygen in the graphene oxide precursor, the oxygen surface groups acting as reactive sites for doping of N-functionalities and mediating the efficient and uniform assembly of TiO 2 nanoparticles on graphene oxide sheets. The same composites, plus two prepared by simple mixing and sonication, were then tested in the photocatalytic degradation of diphenhydramine under near-UV/Vis radiation. Those with graphene oxide (GOT-H and GOT-B) exhibited the highest photocatalytic activity ( k app   =  52.5 × 10 −3 and 51.3 × 10 −3  min −1 , respectively), ascribed to the largest blue shift of the band in the UV range and lowest photoluminescence intensity in the visible range. Thus, reduction of graphene oxide has a negative effect in the case of photocatalysis. [ABSTRACT FROM AUTHOR]

Most heterogeneous catalysts available for catalytic ozonation are present as powders and not ideal for column operation in advanced water treatment. In this study, a mesoporous Ce-Ti-Zr ternary oxide (CTZO) millisphere of large size (0.8–1.0 mm in diameter) and high surface area (180 m 2  g −1 ) was synthesized as a highly stable catalyst to meet the hydrodynamic demand in column ozonation. The fraction of Ce(III) is much higher on the surface of CTZO (49.2%) than CeO 2 (27.5%), resulting in its high catalytic activity in ozone decomposition and mineralization of oxalic acid (OA), an ozone-refractory probe compound. The most favorable catalytic ozonation of OA was observed at pH 3.0 and the adsorption of OA by CTZO via surface complexation is a requisite step for its ozonation. The EPR analysis and radical scavenging experiment confirmed that OH was the dominating reactive species in catalytic ozonation of OA by CTZO. XPS revealed that the oxidation of OA was mediated by the Ce(III)/Ce(IV) redox cycle, which continously accepts the electron supply from OA ligand and meanwhile donates electron to activate O 3 into OH. The catalytic ozonation of OA by CTZO was enhanced in the presence of sulfate due to the generation of sulfate radical. Cyclic runs demonstrated that the CTZO millispheres exhibited high stability for sustainable catalytic ozonation of OA without noticeable release of Ce or change of Ce valence state. This study will provide new insight for the development of efficient ozonation catalysts towards practical application in advanced water treatment. [ABSTRACT FROM AUTHOR]

Most of the calcium peroxide (CaO 2 ) based Fenton oxidation studies focus on the individual pollutant degradation. In this study, the simultaneous oxidation of benzene, toluene, ethylbenzene, and xylene (denoted as BTEX) by CaO 2 based Fenton system was demonstrated. It was observed that BTEX removal increased with increasing molar ratios of CaO 2 /Fe(II)/BTEX. In the case of CaO 2 /Fe(II)/BTEX molar ratio of 5/5/1, BTEX removal were 35% in the ultrapure water and 15% in the actual groundwater. In the case of CaO 2 /Fe(II)/BTEX molar ratio of 40/40/1, BTEX removal were elevated to 98% in the ultrapure water and 88% in the actual groundwater. Chelating Fe(II) agents, such as citric acid (CA), oxalic acid (OA), and glutamic acid (GA), significantly enhanced the destruction of BTEX. When the molar ratio of Fe(II)/CA, Fe(II)/GA, and Fe(II)/OA was 10/20 while fixing CaO 2 /Fe(II)/BTEX molar ratio of 10/10/1, the enhancements in BTEX removal were 60%, 32%, and 72%, respectively. In terms of BTEX removal, OA chelated Fe(II) was demonstrated to be most effective in the CaO 2 /Fe(II)/BTEX system. Based on TOC analysis, the transformation effect was confirmed. The transformation products of BTEX were determined and oxidation pathways were proposed, in which HO was mostly responsible to the parent compounds mineralization. [ABSTRACT FROM AUTHOR]

Being that the influence of organic ligands on contaminant removal by nanoscale zero valent iron (nZVI) has been explored in quite a few studies, there is little information on reaction mechanisms of the ZVI-ligand system under different aeration conditions. The degradation of nitrobenzene (NB) by nZVI-oxalic acids (OA) was investigated under N 2 , O 2 and without aeration conditions. From the findings, it was evident that OA dramatically improved NB degradation by nZVI with all of the aeration conditions. Approximately 100% of NB was degraded by nZVI-OA+N 2 system after 60 min of reaction, followed in effectiveness by nZVI-OA+ without aeration (95%) as well as nZVI-OA+O 2 (85%). Operation parameters including OA concentration and pH had significant effect on the removal of NB in the nZVI-OA system. 3 mM OA concentration and pH 3.0 were found to be favourable. The Fe 2+ , total dissolved iron concentrations, pH and ORP values in the nZVI-OA systems had also been monitored. Intermediates and trapping experiments showed that reduction played a fundamental role in the NB degradation by nZVI-OA under N 2 or without aeration conditions. The formation of Fe(OA) 0 and Fe(OA) 2 2− complexes had lower standard ORP, which could improve the strength of reductant in the systems, and thus resulting in an increased degradation efficiency of NB by nZVI-OA+N 2 . Under O 2 aeration condition, the NB degradation process could be regarded as an oxidation. In the meantime, OA promoted the production of reactive oxidants species by speeding up the oxidation rates of Fe 2+ by O 2 and H 2 O 2 . Summarily, the improved reactivity of nZVI was largely as a result of the strong complexation ability of OA. [ABSTRACT FROM AUTHOR]

While zero-valent iron (ZVI) has been demonstrated to reduce bromate to bromide, ZVI rapidly loses its reductive power because it is oxidized and a passivation layer forms on its surface. In this study, oxalic acid (OA) is introduced to prevent the formation of passivation layer and maintain reductive reactivity of acid-washed ZVI (AZVI). Despite the fact that AZVI is able to remove bromate, bromate reduction by AZVI is remarkably enhanced in the presence of a very small amount of OA (250 μM). OA can coordinate with oxidized iron species (Fe 3+ ) and thus prohibit the formation of passivation layer of iron oxides and hydroxides, allowing AZVI to remain highly reactive for reducing bromate to bromide completely. AZVI + OA also exhibits much lower activation energy than AZVI, indicating that AZVI + OA is much preferred for bromate reduction over AZVI. While bromate reduction by AZVI is considerably hindered under alkaline conditions, the presence of OA lessens the adverse effect and especially retains the reductive reactivity of ZVAI under weakly alkaline conditions. OA is also proven to make AZVI highly reactive even in the presence of co-existing anions without efficiency loss. More importantly, the presence of OA enables AZVI to be reused for bromate reduction quite efficiently even without acid-washing regeneration. These findings reveal that OA-mediated AZVI can enhance bromate reduction, enable AZVI to be highly reactive even under unfavorable conditions, and improve recyclability of AZVI for bromate reduction. These features validate that introduction of OA into bromate reduction by AZVI is advantageous and promising. [ABSTRACT FROM AUTHOR]

Efficient removal of low-concentration HCHO at room temperature and high space velocity without using noble metals is still a great challenge to date. In this work, we have fabricated partially crystallized mesoporous MnO x by redox precipitation reaction between potassium permanganate and oxalic acid, followed by NaBH 4 post-treatment at room temperature. The as-synthesized MnO x was coated on honeycomb ceramics and the obtained monolithic catalyst exhibited high efficiency in removing low-concentration HCHO (1 ppm and 0.2 ppm) at a space velocity of ∼48,000 h −1 . When operated at 85 °C, the monolithic catalyst showed further improved HCHO removal efficiency and durable performance. And with humidity, the catalyst also showed enhanced catalytic activity and prolonged life. The multiple valence states of Mn, high surface area together with the high content of surface-adsorbed oxygen species have been identified and proposed to be responsible for its high catalytic activity in HCHO oxidation removal. [ABSTRACT FROM AUTHOR]

In this paper, a modified mesoporous Fe-MCM-41 based catalyst was synthesized and evaluated in removal of oxalic acid by catalytic ozonation. With the introduction of two active metal oxides (i.e. manganese and cerium oxides) at various loadings on Fe-MCM-41, the elimination of oxalic acid was increased to 83% from its initial concentration. The catalytic activity was found to strongly depend on the proportions of the active compounds. Cerium oxide was more effective active compound than manganese oxides because it led to higher degradation efficiency of oxalic acid. The iron content and the proportions of the metal oxides loadings were optimized. The application of optimum catalyst formulation (0.75 wt% manganese oxides and 1.19 wt% cerium oxide on Fe-MCM-41 with 1 wt% iron content) in the presence of ozone was found to be remarkably promising in degradation of oxalic acid. The optimum supported catalyst could practically remove 94% of the oxalic acid. It was observed that the higher adsorption of oxalic acid on the catalyst samples, the higher elimination of oxalic acid by catalytic ozonation. Therefore, it was deduced that the adsorption of oxalic acid influenced the catalytic activity of the supported catalysts. It is believed that the oxidation of adsorbed organic pollutant on the surface predominantly occurred during the catalytic ozonation processes. [ABSTRACT FROM AUTHOR]

• Interface engineering by introducing three dicarboxylic acids (DAs) including oxalic acid (OA), propanedioic acid (PA) and succinic acid (SA) to modify SnO 2 /perovskite interface. • DAs modification improves both charge transfer and perovskite quality. • The OA-modified PSC achieves higher device efficiency (PCE = 22.91 %) and stability than the reference device (PCE = 21.20 %). Tin dioxide (SnO 2) is considered to be one of the most promising electron transport layers (ETLs) in perovskite solar cells (PSCs). Considering high concentrations of defects and energy level mismatch at the ETL/perovskite interface, buried interfacial engineering aids in boosting the efficiency and stability of PSCs. Herein, three dicarboxylic acids (DAs) including oxalic acid (OA), propanedioic acid (PA) and succinic acid (SA) are selected to modify the interface between perovskite layers and ETLs. It is demonstrated that DAs can enhance interfacial interaction between SnO 2 and perovskite by esterification reaction and hydrogen bonding. In particular, OA with appropriate size can passivate two hydroxyl groups on SnO 2 surfaces simultaneously, resulting in more favorable energy level alignment and better defect passivation ability amongst the three dicarboxylic buffer layers. Correspondingly, the power conversion efficiency of the OA-modified PSC increases substantially from 21.20% (reference device) to 22.91%, with a fill factor up to 83.1%. This work verifies that the buried interfacial engineering can effectively improve PSC performance, and also suggests the possibility of using size-matched symmetric molecules to modify ETLs for performance enhancement. [ABSTRACT FROM AUTHOR]

Novel spherical molecularly imprinted polymer (MIP) particles containing amide-decorated nanocavities with CO 2 recognition properties in the poly[acrylamide-co-(ethyleneglycol dimethacrylate)] mesoporous matrix were synthesized by suspension polymerization using oxalic acid and acetonitrile/toluene as dummy template and porogen mixture, respectively. The particles had a maximum BET surface area, S BET , of 457 m 2 /g and a total mesopore volume of 0.92 cm 3 /g created by phase separation between the copolymer and porogenic solvents. The total volume of the micropores (d < 2 nm) was 0.1 cm 3 /g with two sharp peaks at 0.84 and 0.85 nm that have not been detected in non-imprinted polymer material. The degradation temperature at 5% weight loss was 240–255 °C and the maximum equilibrium CO 2 adsorption capacity was 0.56 and 0.62 mmol/g at 40 and 25 °C, respectively, and 0.15 bar CO 2 partial pressure. The CO 2 adsorption capacity was mainly affected by the density of CO 2 -philic NH 2 groups in the polymer network and the number of nanocavities. Increasing the content of low-polar solvent (toluene) in the organic phase prior to polymerization led to higher CO 2 capture capacity due to stronger hydrogen bonds between the template and the monomer during complex formation. Under the same conditions, molecularly imprinted particles showed much higher CO 2 capture capacity compared to their non-imprinted counterparts. The volume median diameter (73–211 μm) and density (1.3 g/cm 3 ) of the produced particles were within the range suitable for CO 2 capture in fixed and fluidized bed systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3D printing TiOx anode for the first time. • Efficient degradation/mineralization of paracetamol (PCT) as model pollutant. • 3.3- and 1.7- times faster degradation of PCT compared to TiOx and BDD plate anodes. • High mineralization efficiency (75%) at 2 h compared to BDD anode (66%) • 3D printing electrode material with suitable porous structure favors mass transport. 3D printing was used for the first time for synthesis of a 3D TiO x electrode applied to the removal of organic compounds from water by electrooxidation process. After characterization of the synthetized material, effectiveness and reaction mechanisms of the electrode for water treatment was assessed under galvanostatic mode through (i) using probe molecules (terephthalic acid and oxalic acid) and paracetamol (PCT) as model compound (ii) monitoring the fate of degradation by-products and mineralization yields, and (iii) quenching experiments using ethanol to clarify oxidation mechanism. Results emphasized that the suitable porous structure of the 3D TiO x promoted both direct electron transfer and hydroxyl radical-mediated oxidation at the electrode surface. Compared to Ti/TiO x and BDD (boron-doped diamond) plates, 3D TiO x anode achieved faster degradation of PCT (3.3- and 1.7- times enhancement, respectively), lower accumulation of degradation by-products and higher mineralization yield (75% vs 15% and 66%, for Ti/TiO x and BDD anodes, respectively, after 2-h treatment, under similar operating conditions). This study highlights the potential of 3D printing for designing electrode materials with suitable porous structure able to favor mass transport conditions and consequently enhance the efficiency of electrochemical advanced oxidation processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxalic acid (OA) and protocatechuic aldehyde (PA) can inhibit nitrification. • Synthetic pathways of OA and PA were constructed and some key genes were selected. • Inhibition mechanism of OA and PA on Nitrosomonas europaea was revealed. • Inhibitory effect of PA and OA on different agricultural soils was explored. Our research aimed at finding potential BNI resources and exploring the action mechanisms by multiomics. Here, we presented that the Suaeda salsa leaf extracts of both red and green phenotypes from the Yellow River Delta of China showed strong nitrification inhibition ability and selected oxalic acid (OA, molecular weight: 90) and protocatechuic aldehyde (PA, molecular weight: 138) as novel BNIs, then constructed the synthetic pathways and selected some key genes that may influence the synthesis of these two BNIs; and the inhibition mechanisms of these two BNIs on Nitrosomonas europaea were also revealed by performing transcriptomics and metabolomics; and we also found that PA had a nitrification inhibition effect among saline-alkali soil, cinnamon soil and red soil, and the inhibition effect in saline-alkali soil was the most effective, while OA only showed nitrification inhibition effect in red soil. Our findings pointed out a novel plant species as potential BNI resource, and provided opportunities for the design of novel fertilizers, which could improve the crop N utilization efficiency and reduce N loss in agricultural systems. [ABSTRACT FROM AUTHOR]

• The biomass-derived acid is used as the cathode modifier of organic solar cells. • The influenced intermolecular stacking is observed based on these acids. • The interlayer on oxalic acid helps to form a good ohmic contact. • The cells on oxalic acid modified PDIN shows the highest efficiency of 18.43%. The cathode interlayer modification is crucial for the performance of organic solar cells (OSCs), which ensures an efficient electron extraction. However, the research progress of the cathode interlayer is seriously lagging behind, compared with the emerging of OSCs. In this research, three different biomass-derived acid, oxalic acid, azelaic acid and tannic acid, are investigated as the modifiers for the PDIN cathode interlayer of the non-fullerene acceptor based OSCs. The best performance is obtained via the modification of oxalic acid, due to its small conjugated molecule structure. It improves the cathode interlayer quality without disrupting the intermolecular stacking of PDIN. After the modification of oxalic acid, the energy barrier between the active layer and the cathode interlayer is reduced and the carrier recombination is suppressed. It helps the formation of a good ohmic contact and enhances the electron collection. Therefore, the average power conversion efficiency increases from 17.61% of the control device to 18.28%, with a champion efficiency of 18.43%. This research first demonstrates the application of biomass-derived acid in the cathode interlayer modification. It offers a novel strategy to achieve high-efficient cathode interlayer for OSCs using biomaterials. [ABSTRACT FROM AUTHOR]

The use of heavy metals or rare noble metal doping on nanoscale zerovalent iron (NZVI) generally enhances the treatment of hazardous chlorinated organic chemicals (COCs). To avoid the metal use, the effects of four short-chain organic acids (SCOAs) on the degradation of COCs by NZVI were evaluated. Pentachlorophenol (PCP) was the target COC because it has caused serious soil and groundwater contamination. Our results showed that PCP could not be removed by NZVI alone, and the addition of SCOAs promoted PCP degradation by NZVI in acid conditions. Oxalic acid (OA) enhanced the PCP degradation by NZVI more than the other three selected SCOAs. The formation of oxalate-iron complexes out of NZVI particles was observed, indicating that OA could strongly complex with ferrous ions produced during PCP dechlorination and decrease the formation of ferrous (hydro)oxides, which would precipitate on the NZVI surface. Consequently, less passivation layers and even fresh NZVI surfaces were obtained. A more complete PCP dechlorination and the degradation pathways were proposed according to the identification of degradation byproducts. OA led to the highest efficiency of PCP dechlorination around 89% by NZVI due to its strong complexating and pH buffering properties. This green treatment strategy, without doping secondary metals, can facilitate the decontamination of polychlorinated organic pollutants. [ABSTRACT FROM AUTHOR]

The present study considers a scale-up methodology for photocatalytic slurry reactors. The Photo-CREC Water units used include: (a) a 2.65 L internally irradiated annular photoreactor, (b) a 9.8 L externally irradiated scaled-up unit. The LVREA (Local Volumetric Rate of Energy Adsorption Field) calculations for the bench-scale and the scaled-up reactors at different operation conditions are determined by using approaches established by Valades-Pelayo et al. [40] and Valades-Pelayo et al. [41]. In the bench-scale photoreactor, degradations of oxalic acid are carried out at different photocatalyst concentrations and lamp emissions. Residence time distributions are determined for both the Photo-CREC Water II and the Photo-CREC Water III by using glucose as a tracer. An efficiency factor is calculated in both cases including mixing mechanisms and charge/recombination phenomena using a simplified kinetic model. To avoid cross-correlation issues, all relevant parameters are determined by independent experiments. Model validation is also accomplished by comparing model predictions to experimental degradation rates at different photocatalyst concentrations in the larger Photo-CREC Water III. The proposed methodology confirms the applicability of reaction engineering principles for scale-up, from bench to pilot-plant photoreactors. [ABSTRACT FROM AUTHOR]

This article reports a modified recipe to produce multilayers graphene oxide nanoribbon, MLGOR, via lengthwise cutting and unraveling of multiwall carbon nanotube, MWCNT. The modified recipe depends on the intercalation of MWCNTs before unzipping by oxalic acid. The oxalic acid was selected owing to its ability to diffuse through the walls of the MWCNT because it has a molecular length equals the space between carbon walls. This step enables the oxidizing agent to smoothly cut the MWCNT along its longitudinal axis till reach to the interior tube and inhibit the destruction of the MWCNT during unzipping process. This step was confirmed by the TEM measurement. The mechanism of unzipping was investigated extensively by XRD, XPS and Raman spectroscopy. The results showed that each MWCNT is efficiently unzipped to MLGOR at 700 wt% oxidizing agent. The optical and electrochemical band gap of the produced intercalated MLGOR was about 1.5 eV. [ABSTRACT FROM AUTHOR]

Microwave-assisted catalytic solvolysis of lignin in formic acid was studied concerning the addition of HUSY catalysts modified by oxalic acid. Characteristics of the modified catalysts were examined by XRD, NH 3 -TPD and BET. The highest yield of liquid product was achieved as 88.28 wt% (aromatic monomer fraction as bio-oil 1 of 15.36% and oligomer fraction as bio-oil 2 of 67.52%) with the addition of HUSY modified by 0.2 mol/L oxalic acid (HUSY-0.2 M). The production of aromatic monomers in bio-oil 1 identified by GC/MS was enhanced with the addition of HUSY catalysts regardless of acidic treatment, and achieved the maximum value for HUSY-0.2 M experiment. Aromatic oligomers with molecular weight of 328, 342, 358, 378, 394, 424 and 454 were characterized by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) analysis. Formation of almost all identified oligomers was promoted with catalytic experiments with HUSYs except that of 328, extent of which is significantly determined by the pore size, Si/Al ratio and acidic site distribution of the modified catalysts. [ABSTRACT FROM AUTHOR]

We have investigated a photocatalytic ozonation system of seven metal oxide semiconductors, TiO 2 (P25), Nb 2 O 5 , SnO 2 , WO 3 , Fe 2 O 3 , In 2 O 3 , and BiVO 4 , under visible light both with and without UV irradiation for their efficacy in removing total organic carbon (TOC) from aqueous oxalic acid solution for water treatment. The investigation revealed that all the metal oxide samples functioned as photocatalysts for the photocatalytic ozonation system. TiO 2 exhibited the highest activity under UV irradiation, and also exhibited a little activity under visible light irradiation. WO 3 , Fe 2 O 3 , In 2 O 3 , and BiVO 4 functioned as visible-light-responsive photocatalysts and Fe 2 O 3 , In 2 O 3 , and BiVO 4 were newly identified as active photocatalysts under visible light irradiation for the photocatalytic ozonation system. It is suggested that WO 3 is a promising material for the photocatalytic ozonation system due to its activity in the wavelength range of solar energy. [ABSTRACT FROM AUTHOR]

The current report deals with the synthesis of a new and excellent fluoride sorbents using dicarboxylic acids like oxalic acid (Ox) malonic acid (MA) and succinic acid (SA) mediated polyacrylamide–zirconium (PAAm–Zr) and zirconium–oxalic acid (Zr–Ox) complexes by one-pot method. Among the synthesized complexes, Ox–PAAm–Zr and Zr–Ox complexes showed higher (double the times) defluoridation capacity (DC) than the other complexes under batch equilibrium mode. Characterizations of the synthesized complexes were carried out to determine the functional groups, surface morphologies, elemental analysis and crystalline nature. Various equilibrium parameters were optimized. The sorption data were well explained by three commonly used isotherms viz., Freundlich, Langmuir and D–R isotherms. Thermodynamic parameters like ΔG°, ΔH° and ΔS° were calculated and predicted the nature of the fluoride adsorption is spontaneous and endothermic. The mechanism of fluoride removal using Ox–PAAm–Zr complex is ligand-exchange mechanism. Suitable regenerant has been identified in desorption studies and the regeneration ability was tested. Also, the practical viability of the material has been verified with field samples collected from nearby fluoride endemic villages. [ABSTRACT FROM AUTHOR]

• Product yield-conversion profiles were insensitive to temperature. • Glycerol, tartronic acid and oxalic acid inhibit the catalyst activity. • Kinetic model parameters were estimated using rate ratios and further refined. • The optimum oxygen pressure for C3 selectivity was found to be 6 bar. • The higher the alkalinity, the higher the C3 yield in the range studied. Glycerol is a major by-product of bio-diesel production and hence its utilization has been an area of high interest in the scientific community. Oxidizing glycerol to high-value products can improve the economics of bio-diesel production. In the present work, we study glycerol oxidation in alkaline medium using an activated carbon supported Palladium catalyst. Kinetic studies have been performed in a batch reactor to study the effect of different parameters such as NaOH concentration, temperature, and pressure. Our results point to product inhibition by adsorbing reactant and product species. We also observe a relative insensitivity of product yields at a given conversion, to the temperature. Our observations further suggest that higher NaOH concentration gives better C3 selectivity while higher oxygen pressure results in lower C3 selectivity. Based on our own studies and the literature available, the most likely kinetic pathway and a kinetic model have been proposed. Our results suggest the possibility that C–C cleavage occurs directly from the primary intermediate aldehydic species, as a result of which, carbon chain scission products (including CO 2) form from very early stages of the reaction. Various strategies such as pooling temperature data to estimate rate ratios prior to full parameter estimation, use of statistical significance tests to reduce model parameters etc have been used to arrive at a minimalistic model still capable of explaining all features of the oxidation. Confidence bounds on the model parameters have been estimated. [ABSTRACT FROM AUTHOR]

Highlights: [•] The effect of clinoptilolite dealumination on the propane–SCR–NO x process is reported. [•] Dealumination was performed using oxalic acid. [•] NO x conversion to N2 is enhanced significantly. [•] Dealumination effect on the zeolite chemical/physical structure is assessed. [ABSTRACT FROM AUTHOR]

Highlights: [•] The frontier molecular orbital theory was applied to explain the oxidation. [•] Initial rates of TOC reduction and oxalic acid production related to E HOMO and χ. [•] The NH4 + production related to the electron density on the α-carbon atom of –NH2. [•] The electron withdrawing effect of –SO3H groups affected the oxidation significantly. [Copyright &y& Elsevier]

Highlights: [•] Surface reaction plays the major role in O3/MnO x /SBA-15 for the removal of oxalic acid. [•] MnO x /SBA-15 benefits adsorption of oxalic acid and initiation of hydroxyl radicals. [•] Protonated surface hydroxyl groups are claimed to be the main active centers. [•] Multivalent MnO x with higher oxidation states contribute to electron transfer. [•] A possible mechanism of catalytic ozonation is proposed. [ABSTRACT FROM AUTHOR]

Highlights: [•] We proposed two-step treatment method to overcome the problem of low selectivity. [•] Valuable chemicals were recovered selectively from biomass through proposed method. [•] The degradation mechanism of cellulose was discussed. [•] New refinery scheme of biomass was proposed. [ABSTRACT FROM AUTHOR]