查找使用阿拉丁产品的科研文献

The performance of mordenite-dispersed and stabilized ferrous sulfide composites for the removal of Cr(VI) from aqueous solutions

Yixin Pan,Leilei Sun,Zhixin Yu,Xiahui Guo,Lujia Chen,Man Huang

In this study, a composite material (FeS-Mor) of nano ferrous sulfide (FeS) and mordenite was prepared by coprecipitation method using mordenite as a stabilizer to prevent the aggregation of FeS to achieve the purpose of efficient removal of chromium from water. Experimental results revealed that the optimum pH for Cr(VI) removal was ∼ 2 with a removal capacity of 199.0 mg/g and efficiency of 99.5 % at 303 K. Common co-existing cations of Na + , Ca 2+ and K + promoted the removal efficiency, while Mg 2+ inhibited the removal of Cr(VI). While Common anions of SO 4 2− , CO 3 2− , Cl − and NO 3 − inhibited chromium removal. The pseudo-second-order kinetics model fitted the kinetic removal of Cr(VI) onto FeS-Mor composites best under absent/present co-existing cations, indicating that chemical reduction and complexation dominated the removal process. The thermodynamic results were best described with the Freundlich model and showed an endothermic process of Cr(VI) removal. The FeS-Mor composites with FeS:Mor mass ratio in the range of 1:1–1:2 exhibited the best performance in removal efficiency and reusability. These results reveal that introducing mordenite to develop an efficient FeS-based nanocomposite system can significantly improve the performance of chromium remediation from aqueous solutions.

The self-boosting ultrafast removal of Cr(VI) and organic dye in textile wastewater through sulfite-induced redox processes

Yijin Yuan,Qi Tian,Longzhu Hou,Richuan Rao,Chengli Yao,Haoyan Zhu

The treatment of textile wastewater containing harmful metal ions poses a significant challenge in industrial applications due to its environmental impact. In this study, the use of sulfite for treating simulated dye wastewater containing New Coccine (NC) and Cr(VI) was investigated. The removal of NC was influenced by the redox reaction between Cr(VI) and sulfite, demonstrating a strong self-boosting effect of Cr(VI) on NC removal. Remarkable NC decoloration (95%) and Cr(VI) reduction (90%) were achieved within 1 min, highlighting the effectiveness of the treatment. Quenching experiments and electron paramagnetic resonance (EPR) technology confirmed that singlet oxygen ( 1 O 2 ) was the main oxidative agent for organic dye removal and SO 4 •− , •OH and Cr(V) were also identified as key contributors to NC degradation. The Cr(VI)/sulfite system exhibited higher efficiency in degrading azo dyes, such as NC and Congo Red (CR), compared to non-azo dyes like Methylene Blue (MB). This superiority may be attributed to the action of Cr(V) on azo groups. Additionally, the COD removal experiments were conducted on the actual dye wastewater, showing the excellent performance of the Cr(VI)/Sulfite system in treating industrial textile wastewater. This approach presents a promising strategy for effective “waste control by waste”, offering great potential for addressing challenges related to dye wastewater treatment and environmental pollution control in practical industrial scenarios.

New insight into the effects of p-benzoquinone on photocatalytic reduction of Cr(VI) over Fe-doped g-C3N4

Shi-Wen Lv,Jialu Pan,Xiaoran Wang,Yifan Shao,Yanqing Cong,Lin Che

It is of great significance to establish an effective method for removing Cr(VI) from wastewater. Herein, Fe-doped g-C 3 N 4 (namely Fe-g–C 3 N 4 –2) was synthesized and then employed as photocatalyst to conduct the test of Cr(VI) reduction. Notably, the embedding of Fe ion in g-C 3 N 4 can offer the Fe 2+ /Fe 3+ redox couples, so reducing the interfacial resistance of charge transfer and suppressing the recombination of photogenerated electrons and holes. The impurity energy levels will form in g-C 3 N 4 after the introduction of Fe ion , thereby boosting the light absorption capacity of catalyst. Thus, Fe-g–C 3 N 4 –2 showed good performance in photocatalytic Cr(VI) reduction, and the reduction efficiency of Cr(VI) can reach 39.9% within 40 min. Different with many previous studies, current work unexpectedly found that the addition of p -benzoquinone (BQ) can promote the Cr(VI) reduction, and the reduction efficiency of Cr(VI) over Fe-g–C 3 N 4 –2 was as high as 93.2% in the presence of BQ (1.5 mM). Further analyses showed that BQ can be reduced to hydroquinone (HQ) by photogenerated electrons, and UV light can also directly induce BQ to generate HQ by using H 2 O as the hydrogen donor . The HQ with reducing ability can accelerate the Cr(VI) reduction. In short, current work shared some novel insights into photocatalytic Cr(VI) reduction in the presence of BQ. Future research should consider possible reactions between photogenerated electrons and BQ. For the UV-induced photocatalysis , the suitability of BQ as the scavenger of O 2 •‒ must be given carefully consideration.

Phase engineering and morphology modulation of Cu–S induced by Cr introduction for improved electrocatalytic hydrogen evolution reaction performance

Xitao Qiao,Shuaidong Wang,Xin Han,Jiaye Qin,Yanyan Wang,Guangke Tian

Cu 2 S and Cu–S based materials with the introduction of 15 at% and 63% at% Cr respectively were prepared on carbon cloth (CC) (Cu 2 S/CC, Cu 5.6 CrS 6 /CC and CuCr 1.4 S 5 /CC) by one-pot hydrothermal synthesis. It was found that the phase composition and morphology of Cu–S undergo significant changes with the introduction of Cr content, thereby impacting their electrocatalytic hydrogen evolution reaction (HER) properties. In particular, for Cu 5.6 CrS 6 /CC, 15 at% Cr introduction facilitated the formation of a highly catalytically active Cu 7 S 4 -dominant phase and a hexagonal flake-like morphology with a large specific surface area conducive to fully exposing the catalytically active sites. The synergistic advantages in morphology and phase composition endow Cu 5.6 CrS 6 /CC with the best HER electrocatalytic performance with a low overpotential of 81 mV (10 mA cm −2 ) and 142 mV (100 mA cm −2 ), a Tafel slope of 43 mV dec −1 , and 10000 cycle stability. This study provides an idea for implementing a synergistic strategy of phase engineering and morphology modulation by introducing Cr to construct high-performance HER catalysts.

Synthesis of near-spherical W-Cr2O3 composite powders with varying Cr doping levels and their application in cemented carbides

Bin Li,Hongyu Ren,Shengda Guo,Jianbo Zhang,Zhihui Zhou,Bin Zeng,Xiangfei Guo

Tungsten powder is an essential raw material for producing tungsten carbide powders and tungsten-based alloys. However, the fabrication of high-performance spherical tungsten powders remains costly, and achieving a uniform distribution of doped elements poses significant challenges. In this study, a molecularly homogeneous W-Cr precursor solution was prepared using soluble salts, namely ammonium metatungstate ((NH 4 ) 6 [H 2 W 12 O 40 ]·xH 2 O)) and ammonium chromate ((NH 4 ) 2 CrO 4 ). Near-spherical W-Cr 2 O 3 composite powders with various Cr doping contents were synthesized through spray drying, calcination, and low-temperature hydrogen reduction. Subsequently, WC-10Co-xCr cemented carbides were fabricated via spark plasma sintering (SPS) following carburization. The effects of reduction temperature and Cr content on the morphology and phase composition of the W-Cr 2 O 3 composite powders were systematically examined. In addition, the influence of Cr doping on the mechanical properties of the cemented carbides was preliminarily evaluated. The results reveal that, at a reduction temperature of 900 °C and a Cr doping level of 0.5 wt%, the W-Cr 2 O 3 composite powders exhibit a uniform near-spherical morphology with fine and consistent particle sizes. The corresponding cemented carbide demonstrates superior overall performance. Furthermore, the Cr element is uniformly dispersed throughout the WO 3 precursor, W-Cr 2 O 3 composite powders, and the final alloy matrix.

Nano zero-valent iron supported by macroporous styrene ion exchange resin for enhanced Cr(VI) removal from aqueous solution

Wei Gao,Dengjie Zhong,Yunlan Xu,Han Luo,Sijing Zeng

A novel process for comprehensive resource utilization of hazardous chromium sludge: Progressive recovery of Si, V, Fe and Cr

Yun Guo,Hong-Yi Li,Shuo Shen,Jie Cheng,Jiang Diao,Bing Xie

Chromium sludge is a hazardous solid waste which cannot be effectively treated but only piled up and abandoned, causing serious environment pollution and resource wasting. This work proposes an effective novel process to separately recover all resources in chromium sludge via a sustainable way. The obtained acid solving liquid from chromium sludge is desiliconized by cationic flocculant (PCAM) to induce coprecipitation of polysilicate gel and PCAM , which mixture is calcinated to generate the product of white carbon black in purity of 94.35% with a recovery of 92.58%. After desiliconization, V in the solving liquid is selectively extracted by microemulsion (ME), which is recovered as V 2 O 5 in purity of 99.34% with a recovery of 95.53% by the subsequent procedure of stripping-precipitation-calcination. The Fe 3+ in raffinate is reduced to Fe 2+ cations by Na 2 SO 3 , and is then recovered by H 2 C 2 O 4 precipitation to generate the FeC 2 O 4 product in purity of 99.12% with a recovery of 98.25%. Cr 3+ cations in residual solution are recovered by alkaline precipitation and calcination to generate the Cr 2 O 3 product in purity of 98.25% with a recovery of 92.68%. This work provides fresh penetrations into the synchronous detoxification, resource recovery and value-added utilization of hazardous industrial solid wastes.

Novel functional fiber loaded with carbon dots for the deep removal of Cr(VI) by adsorption and photocatalytic reduction

Junfeng Xiao,Yuanpeng Cheng,Caixia Guo,Xiangting Liu,Bing Zhang,Siguo Yuan,Jiajia Huang

A novel functional fiber (PAN-CDs) loaded with carbon dots (CDs) with excellent photoreduction and adsorption properties for Cr(VI) was prepared via an amidization reaction between the CDs' carboxyl groups and amine groups on polyacrylonitrile (PAN)-based ion exchange fibers, which could completely preserve the fluorescence properties of the CDs. The photoluminescence (PL), photocatalysis and adsorption properties of PAN-CDs were characterized and analyzed. The PAN-CDs possess high adsorption capacity (297.6 mg/g) and excellent kinetic behavior (attaining adsorption equilibrium in 30 min) for Cr(VI) adsorption. Furthermore, the residual Cr(VI) (approximately 3 mg/L) after adsorption could be removed completely by subsequent photoreduction by the PAN-CDs. The Cr-saturated PAN-CDs could be easily separated by filtering and regenerated, with no observable decay of removal efficiency after five regeneration cycles. In addition, due to the PL quenching action of Cr(VI), the PAN-CDs can also be used as sensor for quantitative detection of trace Cr(VI) in aqueous solution.

Hybrid silsesquioxane-based porous polymer/chitosan aerogel for visible-light-driven degradation of antibiotics and reduction of Cr (VI)

Xiaohan Zhao,George K. Belousov,Sergei V. Kostjuk,Aliaksei Vaitusionak,Hongzhi Liu

A silsesquioxane-based hybrid porous polymers (PCS-SC-3) was successfully constructed via free-radical polymerization. • PCS-SC-3 exhibited efficient visible-light-driven photocatalytic performance for simultaneous Cr (VI) reduction and tetracycline degradation. • A flexible chitosan-based hybrid aerogel (PCS-SCA) was fabricated, achieving over 96% antibiotic removal efficiency with excellent reusability. A new organic semiconductor molecule 9, 9′, 9″, 9‴-(4-(trifluoromethyl)-4′-vinyl-[1, 1′-biphenyl]-2, 3, 5, 6-tetrayl) tetrakis-carbazole (StTCbzCF 3 ), was synthesized and subsequently copolymerized with octavinylsilsesquioxane (OVS) and 9-vinylcarbazole via azobisisobutyronitrile (AIBN)-initiated free-radical polymerization, yielding organic-inorganic hybrid porous polymers (PCS-SC-x (x = 1, 2, and 3; where x denotes the mass percentage of StTCbzCF 3 in the synthesized polymers: 20% (x = 1), 40% (x = 2), 60% (x = 3)). Among these materials, PCS-SC-3 exhibited a high specific surface area (478 m 2  g −1 ), a large Stokes shift (115 nm), and stable fluorescence. Notably, in the absence of sacrificial agents, 93% of Cr (VI) was photocatalytically reduced to the less toxic Cr (III) within 95 min under simulated sunlight, while >90% removal was retained after five cycles. In addition, PCS-SC-x (x = 1, 2, 3) was also demonstrated to function as a visible-light-driven photocatalyst for tetracycline hydrochloride (TCH) degradation. More than 95% of TCH was degraded within 75 min under visible light irradiation, with an initial pseudo-first-order rate constant of 0.0641 min −1 , which was higher than most previously reported photocatalysts. In the coexisting Cr (VI)/TCH system, the removal of both pollutants was enhanced; with the Cr (VI) reduction rate constant reaching 0.0713 min −1 , which was 2.05 times that obtained in the single-component system, indicating enhanced simultaneous remediation of the two pollutants. Radical-trapping experiments revealed that superoxide radicals (·O₂ − ) played a dominant role in the degradation pathway. PCS-SC-3 was further integrated with chitosan to fabricate a monolithic aerogel (PCS-SCA), which enabled efficient antibiotic degradation in a continuous-flow system and maintained a TCH removal efficiency of >96% after five cycles. This work provides a scalable, metal-free strategy for the integrated remediation of Cr (VI) and antibiotic contaminants and offers a facile and environmentally friendly route for the fabrication of flexible hybrid aerogels for practical water-treatment applications.

Efficient adsorption H3AsO4 and Cr(VI) from strongly acidic solutions by La-Zr bimetallic MOFs: Crystallinity role and mechanism

Caiyun Han,Jing Xie,Xize Min

Due to the non-degradable of heavy metal, adsorption has been extensively applied to abatement it. Most studies were focused on uptake metal ions via electrostatic attraction and ion exchange, and load molecule H 3 AsO 4 from strongly acidic wastewater was still challenging. To solve the problem, bimetallic La–Zr MOFs was facilely fabricated in this work, and the fcu topology structure of La-Zr MOFs was remained well under the investigate crystallization time and crystallization temperature. However, the crystallinity of the obtained La-Zr MOFs was influenced by the synthesized factors. The obtained La–Zr MOFs was employed as adsorbent to removal Cr(VI) and As(V), and the performance was evaluated by the batch experiment. The result indicated that the adsorption performance of Cr(VI) and As(V) was positively correlated with the crystallinity , and the optimal sample was 1LaUN 12 . From the XPS characterization, it was found that H 3 AsO 4 was successfully uptake over 1LaUN 12 surface, and the maximum monolayer adsorption capacity was 83.40 mgH 3 AsO 4 /g via ligand exchange and coordination reactions with La−OH and Zr−OH. In addition, the sample 1LaUN 12 also exhibited the excellent Cr(VI) load performance, and the maximum monolayer adsorption capacity of Cr(VI) was 222.5 mg/g. Above 40% Cr(VI) was reduced to Cr(III) by amino groups, and immobilized over the surface of 1LaUN 12 . Eventually, 1LaUN 12 displayed a good structural stability in the acidic medium, which was in favor of removing Cr(VI) and As(V) efficiently from strongly acidic solutions.

Microwave-assisted synthesis of Zr-based metal-organic polyhedron: Serving as efficient visible-light photocatalyst for Cr(VI) reduction

Yu-Teng Zhang,Juan Zhu,Zhao-Yang Liu,Shuang-Bao Li,He Huang,Bao-Xu Jiang

For the first time, a microwave-assisted synthesis approach was used to prepare an amino-functionalized Zr-based metal–organic polyhedron (denoted as MW-ZrT-1-NH 2 ). The reaction time was shortened from 12 h to 2 min when compared to the traditional solvothermal method, resulting in crystalline products with good yield and purity. Herein, MW-ZrT-1-NH 2 was utilized as a photocatalyst for the catalytic reduction of Cr(VI) under visible-light irradiation. The results revealed that MW-ZrT-1-NH 2 exhibits better photocatalytic performance for Cr(VI) reduction. Furthermore, a plausible photocatalytic mechanism was proposed via electron spin resonance (ESR) measurements and radical trapping tests.

Simultaneous Removal of Cr(VI) and Phenol from Water Using Silica-di-Block Polymer Hybrids: Adsorption Kinetics and Thermodynamics

Jia Qu,Qiang Yang,Wei Gong,Meilan Li,Baoyue Cao

Heavy metal ions and organic pollutants often coexist in industrial effluents. In this work, silica-di-block polymer hybrids (SiO2-g-PBA-b-PDMAEMA) with two ratios (SiO2/BA/DMAEMA = 1/50/250 and 1/60/240) were designed and prepared for the simultaneous removal of Cr(VI) and phenol via a surface-initiated atom-transfer radical polymerization process using butyl methacrylate (BA) as a hydrophobic monomer and 2-(Dimethylamino)ethylmethacrylate (DMAEMA) as a hydrophilic monomer. The removal efficiency of Cr(VI) and phenol by the hybrids reached 88.25% and 88.17%, respectively. The sample with a larger proportion of hydrophilic PDMAEMA showed better adsorption of Cr(VI), and the sample with a larger proportion of hydrophobic PBA showed better adsorption of phenol. In binary systems, the presence of Cr(VI) inhibited the adsorption of phenol, yet the presence of phenol had a negligible effect on the adsorption of Cr(VI). Kinetics studies showed that the adsorption of Cr(VI) and phenol fitted the pseudo-second-order model well. Thermodynamic studies showed that the adsorption behavior of Cr(VI) and phenol were better described by the Langmuir adsorption isotherm equation, and the adsorption of Cr(VI) and phenol were all spontaneous adsorptions driven by enthalpy. The adsorbent still possessed good adsorption capacity for Cr(VI) and phenol after six adsorption–desorption cycles. These findings show that SiO2-g-PBA-b-PDMAEMA hybrids represent a satisfying adsorption material for the simultaneous removal of heavy metal ions and organic pollutants.Keywords:silica;amphipathic;block copolymer;adsorption;Cr(VI);phenol