查找使用阿拉丁产品的科研文献

Highly efficient activation of persulfate by encapsulated nano-Fe0 biochar for acetaminophen degradation: Rich electron environment and dominant effect of superoxide radical

Sheng-Nan Zhuo,Hong-Yu Ren,Guang-Li Cao,Guo-Jun Xie,De-Feng Xing,Nan-Qi Ren,Bing-Feng Liu

In this study, an encapsulated nanoscale zero-valent iron biochar (BC-Fe 0 ) derived from waste lignocellulose rice straw (RS) was synthesized. BC-Fe 0 has excellent properties, including long-term stability, a large specific surface area, many micropore structures, active defects active and oxygen-containing groups. The material was first used to activate persulfate (PDS), showing a highly efficient catalysis for acetaminophen (ACT) degradation. The removal efficiency of ACT within 20 min reached 100%, and the degradation rate constant ( k obs ) reached 0.37475 min −1 at the ACT concentration of 10 mg/L, BC-Fe 0 of 0.5 g/L, temperature of 298 K. EPR demonstrated that ·OH, SO 4 −· , ·O 2 − and 1 O 2 occurred during the reaction process, and ·O 2 − , 1 O 2 and electron transfer played major roles in PDS/BC-Fe 0 system. Fe 0 nanoparticles promoted the activation of PDS to generate ·O 2 − , which induced a series of other reactive oxygen species (ROS) to attack ACT. C = O might also contribute to the production of 1 O 2 . In addition, graphitic carbon, C–O, defects and micropores on BC-Fe 0 together created a rich electron environment, which is conducive to the redox reaction between ACT and ROS. Satisfyingly, BC-Fe 0 not only had a high catalytic activation capacity, but also exhibited a desirable durability and recyclability. The development of BC-Fe 0 catalysts and the study of PDS activation for organic pollutant degradation are significant to biomass conversion and advanced oxidation processes in environmental remediation.

Combination of coagulation, Fe0/H2O2 and ultra-high lime aluminium processes for the treatment of residual pollutants in biologically-treated landfill leachate

Xue Bai,Shiqi Mu,Bowen Song,Mingde Xie

MoS2 as highly efficient co-catalyst enhancing the performance of Fe0 based electro-Fenton process in degradation of sulfamethazine: Approach and mechanism

Yusi Tian,Minghua Zhou,Yuwei Pan,Xuedong Du,Qi Wang

Molybdenum sulfide (MoS 2 ) was for the first time used as a co-catalyst to enhance the performance of Fe 0 based heterogeneous electro-Fenton (Fe 0 -EF) process for the degradation of sulfamethazine (SMT), which was belonging to the sulfonamide family and extensively used as growth promoters and antibacterial drugs. Compared with Fe 0 -EF process, MoS 2 /Fe 0 -EF process could enhance the rate constant of SMT degradation 2 times under the optimal conditions of current 50 mA, MoS 2 dosage 0.02 g L -1 , Fe 0 dosage 0.224 g L -1 , and initial pH 4, in which SMT could be completely degraded within 10 min while 42% TOC could be achieved after 60 min reaction. The role of MoS 2 as co-catalyst in MoS 2 /Fe 0 -EF process and Fe 2+ /Fe 3+ cycle was supported by iron elemental analysis, transmission election microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) characterizations. Owing to the characteristics of co-catalysis, MoS 2 could greatly facilitate the Fe 3+ /Fe 2+ recycle reaction by the exposed Mo 4+ active sites, which significantly promoted the decomposition of H 2 O 2 that generated in Fe 0 -EF system and improved the generation of hydroxyl radical. Besides, a possible degradation pathway of SMT was proposed and the stability of MoS 2 /Fe 0 -EF process for SMT removal and TOC mineralization was certified base on five consecutive runs. The real wastewater test and energy consumption and economic analysis confirmed its advantage and cost-effectiveness for application. In all, this study provides a new perspective for improving heterogeneous Fe 0 -EF process with MoS 2 for highly efficient and rapid degradation of antibiotics.

Complexing agent-assisted Cr(VI) removal in a continuous fixed-bed system with nanoscale Fe0/NaA molecular sieve membrane supported on nickel foam

Jian Liu,Xueren Huang,Zhengji Yi

Complexing agents (CAs) can be used for the removal of Cr(VI) via nanoscale Fe 0 (nZVI) reduction in cost-effective manner. However, nZVI is prone to aggregation and passivation, and some conventional CAs are toxic and difficult to biodegrade, potentially causing secondary pollution. Therefore, selecting an environmentally friendly CA for assisting in the removal of Cr(VI) via supported nZVI is imperative. Herein, NaA molecular sieve membrane-supported nZVI (nZVI/NaA-NF) was prepared via the secondary growth and liquid-phase reduction method using nickel foam (NF) as the carrier. The physicochemical characteristics of nZVI/NaA-NF before and after reaction were analysed via SEM, EDS, and XPS. A CA-improved nZVI/NaA-NF was used for the effective removal of Cr(VI) in a continuous fixed-bed system. Furthermore, the influences of various experimental factors including the CA type, CA concentration, solution pH, space velocity, and inlet Cr(VI) concentration on Cr(VI) removal were systematically investigated. The results demonstrated that nZVI particles were homogeneously immobilized on the NaA molecular sieve membrane/NF for fresh nZVI/NaA-NF, and tetrasodium iminidisuccinate (IDS-4Na) inhibited the aggregation of Cr(III)/Fe(III) (hydr)oxide precipitates during the reaction. IDS-4Na demonstrated excellent promotive effect on Cr(VI) removal via nZVI/NaA-NF. The breakthrough time for Cr(VI) in the addition of IDS-4Na was considerably longer than that of nZVI/NaA-NF alone. The breakthrough concentration of Cr(VI) only reached 1.1% and 9.9% of the inlet concentration at 220 and 240 min, with an IDS-4Na concentration of 4 mM, a pH of 2.5, and a space velocity of 0.265 min −1 . The Bohart–Adams model was appropriate to predict the initial part of Cr(VI) breakthrough curves in the nZVI/NaA-NF fixed bed. The saturated concentration ( N 0 ) increased with an increase in inlet Cr(VI) concentration. The Yoon–Nelson model afforded good fitting results for all breakthrough curves of Cr(VI). The k′ value increased with an increase in space velocity, and the τ value decreased.

Overcoming Fe0/Cr(VI) redox-induced low electron transfer efficiency under neutral pH by iron-based dual active sites-mediated hydrogen atom activation

Chundi Zhou,Minghao Sui,Yali Guo,Songhang Du

Efficiently removing hexavalent chromium (Cr(VI)) using iron-based adsorbents under neutral pH conditions continues to pose a challenge. In this study, we constructed nano zero-valent iron (nZVI) supported by carboxylated multi-walled carbon nanotubes (OCNT) composites with iron-based dual active sites through the nitrilotriacetic acid modification (FOC-NA). The acid dissolution experiment, high-resolution transmission electron microscopy (HRTEM), thermogravimetric analyzer (TGA), X-ray photoelectron spectroscopy (XPS), and Raman analysis proved these active sites consisted of iron-carboxylate complex (−COOFe(II)) and OCNT-confined nZVI (Fe 0 -in-OCNT). The existence of iron-based dual active sites enhanced electron transfer efficiency in Cr(VI) removal under neutral pH conditions. This leaded to a superior adsorption capacity for Cr(VI), as evidenced by a maximum adsorption capacity of 141.29 mg·g −1 at a pH of 6.5. Meanwhile, the formation of a Cr-containing product (−COOFe-O-Cr) on the surface of FOC-NA substantially hindered the re-release of chromium into the environment. Furthermore, this study proposed the significant involvement of active hydrogen atoms (H*) in the reduction of Cr(VI), as confirmed by quenching experiments and analyses using electron spin resonance (EPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The formation pathway and energy barrier of H* and the −COOFe-O-Cr complex were analyzed by density functional theory (DFT) calculations. This study provided insights for the rational design of iron-based adsorbents with dual active sites to facilitate the activation of H* for Cr(VI) reduction under neutral pH conditions.

Ball-milled Fe0/FeS2 enhanced interaction of Shewanella oneidensis MR-1 with anaerobic microbial community: Impact on 2,4-dichloronitrobenzene reduction and methane yield

Cholnam Ri,Fengxiang Li,Hyokchol Mun,Linan Liu,Jingchun Tang

The technology of integrating sulfidated zero-valent iron and functional anaerobic bacteria has been extensively explored to improve the removal efficiency of pollutants and enhance the performance of anaerobic microbial system. In this study, the simultaneous DCNB(2,4-dichloronitrobenzene) reduction and methane production by ball-milled 1:1 Fe 0 /FeS 2 (briefly, 1:1 Fe 0 /FeS 2 ), Shewanella oneidensis MR-1 and microbial consortium (MC) were firstly investigated. The result showed that the DCNB reduction was increased by 2.6 and 1.7 times in 1:1 Fe 0 /FeS 2  + MR-1 group compared to 1:1 Fe 0 /FeS 2 and MR-1, respectively, while it further increased by almost 2 times in 1:1 Fe 0 /FeS 2  + MC + MR-1 group as compared to that of 1:1 Fe 0 /FeS 2  + MR-1 group. Moreover, the methane production was drastically facilitated via the reciprocal interaction among FeS as the reaction product, MR-1 and MC. Dechlorination was not found, mainly due to the inability of 1:1 Fe 0 /FeS 2 and the inexistence of dechlorinating bacteria in original inoculum. Meanwhile, the microbial community was also changed, with genera like Eubacterium capable of reducing nitroaromatic compound and Methanosarcina as acetoclastic methanogen enriched by 1:1 Fe 0 /FeS 2 and MR-1. Therefore, fast DCNB reduction and methane production using 1:1 Fe 0 /FeS 2 in anaerobic microbial system, gives useful reference for both establishment of pollutant removal and biogas production. In conclusion, Fe 0 /FeS 2 , as a kind of sulfidated ZVI, is a good candidate for enhancing both pollutant degradation and CH 4 production in anaerobic wastewater treatment.

Effective degradation of 2,4-dihydroxybenzophenone by zero–valent iron powder (Fe0)-activated persulfate in aqueous solution: Kinetic study, product identification and theoretical calculations

Mengting Zou,Yumeng Qi,Ruijuan Qu,Gadah Al-Basher,Xiaoxue Pan,Zunyao Wang,Zongli Huo,Feng Zhu

2,4-Dihydroxybenzophenone (BP-1), a typically known derivative of the benzophenone-type UV filter, has been frequently detected in aqueous environments and poses a potential risk to human health and the entire ecosystem. In this study, an effective advanced oxidation technique using zero-valent iron powder (Fe 0 )-activated persulfate (PS) was used for the degradation of BP-1. The effects of several experimental parameters, including Fe 0 dosages, PS dosages, pH, and common natural water constituents, were systematically investigated. The BP-1 degradation efficiency was enhanced by increasing the Fe 0 and PS dosages and decreasing the solution pH. The presence of different concentrations of humic acid (HA) could inhibit BP-1 removal, while the addition of various cations and anions had different effects on the degradation. Moreover, the degradation of BP-1 in five water matrices was also compared, and the removal rates followed the order of ultrapure water > tap water > secondary clarifier effluent > river water > synthetic water. Thirteen oxidation products were identified by liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS) analysis, and five possible degradation pathways were proposed. The addition reactions initiated by HO and SO 4 − , as well as single-electron coupling reactions and ring-closing reactions, were further supported by density functional theory (DFT) calculations. Assessment of toxicity of intermediates of the oxidation of BP-1 suggested decreased toxicity from the parent contaminant. The present work illustrates that BP-1 could be efficiently degraded in the Fe 0 /PS system, which may provide new insights into the removal of benzophenones in water and wastewater.

Band gap narrowing ternary phosphorus-doped g-C3N4/Fe0@expanded graphite carbon layer hybrid composite for effective degradation of tetracycline via multiply synergistic mechanisms

Xiangyu Wang,Yiming Wang,Jun Ma,Ping Ning

The wide band gap of g-C 3 N 4 and severe aggregation of Fe 0 adequately limit their applications. To address these two critical issues, novel ternary phosphorus-doped g-C 3 N 4 /Fe 0 @expanded graphite carbon layer (P-CN/Fe 0 @EGC) photocatalyst with extremely narrow band gap and significantly enhanced catalytic activity was in-situ synthesized. P-CN/Fe 0 @EGC hybrid composite exhibited excellent photodegradation performance of tetracycline (TC) removal, which is 5.18 and 1.92 times higher than that of pristine g-C 3 N 4 and Fe 0 , respectively. Enhancement in photocatalytic activity is evaluated via photoluminescence (PL), UV–vis DRS, XRD and electron spin resonance (ESR). A reasonable catalytic mechanism of P-CN/Fe 0 @EGC is proposed. The multiply synergistic mechanisms of phosphorus-doped g-C 3 N 4 (P-CN), Fe 0 and expanded graphite carbon layer (EGC), as well as the strong reducibility of Fe 0 were accounted for the expanded visible light absorption range. The even dispersion of Fe 0 on porous and worm-like structured P-CN/EGC effectively and successfully avoided the decline in photocatalytic activity caused by aggregation of Fe 0 nanoparticles . Compared with g-C 3 N 4 , the band gap of phosphorus-doped g-C 3 N 4 was narrowed from 2.79 to 2.60 eV. It is worth noting that Fe 0 plays an important role in accelerating electron transfer speed and efficiency between P-CN and EGC. The·O 2 − and h + were the dominant active substances for TC degradation . Moreover, P-CN/Fe 0 @EGC catalyst could be used repeatedly for at least 7 cycles with high TC removal efficiency. This study may pave a new way on designing high efficient ternary hybrid photocatalyst for antibiotic degradation.

Taping into the super power and magic appeal of ultrasound coupled with EDTA on degradation of 2,4,6-TCP by Fe0 based advanced oxidation processes

Bingzhi Liu,Tingyu Pan,Jiajun Liu,Li Feng,Yuning Chen,Huaili Zheng

Chlorophenol is a widely used organic compound, and the environmental and health problems caused by it have being worsened in recent years. This study used 2,4,6-trichlorophenol (2,4,6-TCP) as the target pollutant, and employed ultrasound (US) enhanced zero-valent iron (Fe 0 )/EDTA/air system (FEA), namely US/FEA, to remove 2,4,6-TCP. The influence of single factor experimental conditions such as EDTA concentration, Fe 0 dosage, US power, pH and pollutant concentration on the removal efficiency of 2,4,6-TCP was investigated, and the optimal reaction conditions were determined. The mechanism of reactive oxygen species (ROS) produced by US/FEA was explored. The degradation process and removal mechanism of 2,4,6-TCP in the US/FEA were discussed through the determination and analysis of intermediate products. The results showed that US could continuously activate and renew the Fe 0 surface, accelerate its oxidation and corrosion process, and then continuously and stably produce sufficient amounts of Fe 2+ and Fe 3+ . Ultrasonic cavitation effect could reduce the difficulty of O 2 activation reaction, and promote the production of sufficient H 2 O 2 . The addition of EDTA made the system have a wide range of pH applications, and its performance under neutral and alkaline conditions was also superior. The ROS of US/FEA included ·OH, O 2 ·- and Fe(IV), where Fe(IV) was the main contributor to the removal of 2,4,6-TCP. In addition, the degradation of 2,4,6-TCP had two processes including dechlorination and benzene ring opening. First, 2,4,6-TCP was dechlorinated and degraded into phenol. And then, phenol was degraded into small molecular acids by ring-opening, and finally it was mineralized into CO 2 and H 2 O completely. US/FEA is a promising technology for high-efficiency degradation of organic matter and deep environmental purification.

Synthesis of Fe0/Fe3O4@porous carbon through a facile heat treatment of iron-containing candle soots for peroxymonosulfate activation and efficient degradation of sulfamethoxazole

Yating Yan,Huayu Zhang,Wei Wang,Wenchao Li,Yueping Ren,Xiufen Li

Developing highly efficient, reusable, non-toxic and low-cost catalysts is of great importance for persulfate-based advanced oxidation processes (AOPs). In this work, ferrocene was mixed into paraffin to prepare a candle, and the iron-containing candle soots were collected and heated at 500 °C~900 °C under N 2 atmosphere for 1 h to prepare magnetically recyclable Fe 0 /Fe 3 O 4 @porous carbon (Fe 0 /Fe 3 O 4 @PC) catalysts. The Fe 0 /Fe 3 O 4 @PC-700 obtained after pyrolysis at 700 °C exhibited the best catalytic activity for sulfamethoxazole (SMX) degradation. 10 mg/L SMX could be completely degraded within 10 min by 0.2 g/L of Fe 0 /Fe 3 O 4 @PC-700 and 0.5 mM PMS at pH 5.0. The carbon shell effectively inhibited the Fe leaching of Fe 0 /Fe 3 O 4 @PC-700, and 99.73% of Fe was retained after five consecutive cycles. In the Fe 0 /Fe 3 O 4 @PC-700/PMS system, SMX was degraded through the sulfate radical (SO 4 · ¯ ), hydroxyl radical (·OH), superoxide radical (O 2 · ¯ ) dominated radical pathway, and the singlet oxygen ( 1 O 2 ) dominated non-radical pathway. The coexisting inorganic ions and natural organic matters (NOM) in actual water inhibited the degradation of SMX. Finally, four possible degradation pathways were proposed based on the degradation intermediates of SMX. This work provides a facile heat treatment of iron-containing candle soots strategy to prepare the metal@carbon catalysts for PMS-based AOP.

Enhanced degradation performance of p-chlorophenol in photo-Fenton reaction activated by nano-Fe0 encapsulated in hydrothermal carbon: Improved Fe(III)/Fe(II) cycle

Qingwen Long,Feng Liu,Yanjie Yuan,Yuting Dai,Chunli Wang,Xuheng Li,Jing Zhang

In this study, heterogeneous Fenton-like catalyst, nano-Fe° encapsulated in hydrothermal carbon (Fe°/HTCC), was prepared via a green chemistry route, aiming at increasing the degradation efficiency of p-chlorophenol (4-CP) by controlling the stability of the catalyst and Fe(III)/Fe(II) cycling in the advanced oxidation process. The degradation of 4-CP by heterogeneous Fenton reactions was conducted with the assistance of visible light, which was monitored with the aid of the HPLC and total organic carbon analysis. The results revealed that Fe°/HTCC composite markedly enhanced both the degradation (100 %) and the mineralization efficiency (∼73.9 %) for 100 mg/L 4-CP within 60 min at pH 4.0. More importantly, the catalyst presented a high stability to resist the side oxidation, where the removal efficiency was maintained even after 5 successive cycling experiments. Electron spin resonance confirmed that in the presence of both HTCC and visible light irradiation greatly enhanced the production of •OH for the degradation and mineralization of 4-CP, which can be attributed to the enhancement of Fe(III)/Fe(II) cycling. This study paves a new way toward the rational design of Fe°–carbon composites as heterogeneous Fenton-like catalysts for potential applications into wastewater treatment.

Electricity generation in fuel cell with light and without light and decomposition of tetracycline hydrochloride using g-C3N4/Fe0(1%)/TiO2 anode and WO3 cathode

Kané Rabé,Lifen Liu,Noor Ahmed Nahyoon

Visible-light-driven photocatalytic Fuel Cell (PFC) is of great interest in the environmental pollutant remediation with energy recovering. Herein, enhancement in photocatalytic degradation of Tetracycline Hydrochloride (TC) with electricity generation was achieved in a single reactor of PFC with paired stainless-steel mesh electrode loaded with anodic g-C 3 N 4 /Fe 0 (1%)/TiO 2 and cathodic WO 3 catalyst (at various pH, 0.05 M Na 2 SO 4 , 10 Ω external resistance) with visible light and without light. With light, TC molecules were successfully removed (97.3% in 90 min, at initial and optimal pH 5), while generating 0.98 V cell voltage and 24 W m −2 power density, simultaneous removal of COD (chemical oxygen demand) and TOC (total organic carbon) was 91.3% and 95%, respectively, suggesting superior mineralization that can be explained by the excitation of the anodic triple component g-C 3 N 4 /Fe 0 (1%)/TiO 2. In contrast, without light, the removal of COD, TOC and the cell voltage were much lower (48.8%, 65.3%, 0.78 V). In dark, the fuel cell is self-driven and self-biased, forming potential gradient and degrading pollutants. The effects of solution pH, initial TC concentration on degradation and power generation were evaluated. This PFC degrading TC can maintain high photocatalytic activity and high power output capacity after 5 cycles with light. Without light, the electricity generation capacity was 50–70% that in visible light PFC. These features reveal that fuel cell with g-C 3 N 4 /Fe 0 (1%)/TiO 2 photo anode and WO 3 photocathode has great application potential for removing refractory pollutants from wastewater.