CHEMOSPHERE
·
2022
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IF 8.943
Xiaoyan Liu,Shenyu Zhang,Xinying Zhang,Hao Guo,Xinde Cao,Ziyang Lou,Wei Zhang,Chuanhua Wang
A novel hydrogel-supported nanoscale zero-valent iron (nZVI) composite (nZVI@LH) was synthesized by ion exchange and in-situ reduction. The removal efficiency was tested, and the mechanism was also explored. The nZVI@LH at the precursor Fe(II) ion concentration of 0.1 mol/L presented an enhanced Cr(VI) removal capacity of 310.86 mg/g Fe 0 at pH 5.3, which was 11.6 times more than that of the pure nZVI. The removal efficiency of the composite at pH 2.1 was more than double compared with alkaline or neutral conditions. Scanning electron microscopy (SEM) suggested that the nZVI particles were uniformly immobilized in the lignin hydrogel. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) provided evidence supporting the removal mechanism. According to the XPS results, the high removal capacity of the composite was attributed to chemical reduction/precipitation (69.7%), surface sorption (19.7%), and swelling uptake (10.6%). The pseudo-first-order reduction kinetics and pseudo-second-order kinetic model were employed to simulate the kinetic data, which supported the mechanism that chemical reduction and surface sorption could simultaneously remove Cr(VI). The electron acceptor and electron donor affected the reaction rate, and the presence of humic acid significantly inhibited the reaction. The present study demonstrated that lignin hydrogel acted as a carrier to prevent aggregation of nZVI particles. nZVI particles loaded on lignin hydrogel showed high reactivity and high degree of utilization compared with bare-nZVI. These results exhibited the great potential of nZVI@LH in practical water treatment due to its high activity.
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高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Peng Liu,Xiaowei Wu,Suyi Pan,Jiamin Dai,Zixuan Zhang,Xuetao Guo
Wastewater treatment plants (WWTPs) are the important source of microplastics (MPs) in the environment, and disinfection processes bear high potential to degrade MPs. This study investigated the physicochemical degradation, dissolved organic products and interaction with co-existed pollutants (heavy metal and pharmaceutical) on polyethylene (PE), polypropylene (PP) and polystyrene (PS) MPs during simulated disinfection processes. Compared to photo or chlorination, photochlorination significantly resulted in the physicochemical degradation, including morphology alteration, fragmentation, and chemical oxidation on PP and PS MPs, but showed relatively low effect on PE, indicating the different resistance among polymers to disinfected treatment. Photochlorination also caused the formation of chain-scission organic compounds and even chlorinated products from MPs (e.g. C 11 H 19 O 4 Cl for PP and monochlorophenol, dichlorophenol, chloroacetophenone and chlorobenzoic acid for PS), which may form disinfection byproducts to induce healthy risk. The adsorption potentials of MPs for Cr(VI) or amlodipine were enhanced by photochlorination since the cracking and formed oxygen functional groups enhanced the pore filling and surface precipitation of Cr(VI), and the electrostatic attraction and hydrogen bonding with amlodipine. The findings indicated the physicochemical degradation of MPs and the combined pollution with co-existed pollutants, highlighting the health risks of MP-derived organic products during the disinfection treatments (even in normal dosage) in WWTPs.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2022
·
IF 6.371
Yuxiang Hua,Chengyao Hu,Muhammad Arif,Shen-ming Chen,Min Zhang,Xiaoheng Liu
The design of efficient and stable photocatalysts for the removal of heavy metals in the environment has become a research hotspot. Here, a composite photocatalyst with three-dimensional In 2 S 3 microspheres supported by WO 3 nanoparticles was synthesized for the photoreduction of Cr(VI) for the first time. The constructed composite catalyst has a direct Z-scheme electron transport mechanism without any precious metals (Au, Pt, and Ag), quantum dots (TiO 2 QDs) or carbon materials (Graphene) as electronic media. Constructing a direct Z-scheme WO 3 /In 2 S 3 photocatalyst can greatly retain the reduction and oxidation reaction sites on the surface of the heterojunction and accelerate the reduction reaction. Under visible light irradiation, it greatly promotes the photocatalytic reduction of Cr(VI), which is 67.7 times and 3.6 times the reduction rates of WO 3 and In 2 S 3 , respectively. The favorable photocatalytic performance of WO 3 /In 2 S 3 should be attributed to the effective interfacial contact between the semiconductors in the Z-scheme system, thereby realizing effective electron transfer and charge separation. In addition, the stability of WO 3 /In 2 S 3 was studied, and a possible mechanism in the photoreduction process of Cr(VI) was proposed.
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INORGANIC CHEMISTRY
·
2022
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IF 5.436
Dexin Wang,Amir Said,Yanshu Liu,Huihui Niu,Caiyun Liu,Guo Wang,Zhaoyang Li,Chen-Ho Tung,Yifeng Wang
The solvothermal reaction of titanium isopropoxide and chromate in the presence of benzoate produced two novel host–guest clusters encapsulating Cs+ or H3O+, (H3O)@Ti7Cr14 and Cs@Ti7Cr14. The most remarkable feature is that the Ti7O7 ring is concentrically embraced by a Cr14O14 ring to form a rigid Ti7Cr14 host. ESI-MS and 133Cs NMR revealed that the overall framework structures are preserved, whereas the benzoate ligands on the two clusters may be labile in solutions. Both (H3O)@Ti7Cr14 and Cs@Ti7Cr14 exhibit good UV–vis light-responsive properties and photocatalytic activities, with absorption edges extending up to 780 nm. Cs@Ti7Cr14 is an effective visible-light-responsive photocatalyst in both the heterogeneous methylene dye degradation and homogeneous CO2 cycloaddition reaction under mild conditions like room temperature and 1 bar of CO2. According to the mechanism studies, Cs+, as a rigid guest, can significantly improve the photogenerated charge separation efficiency of the Ti7Cr14 host, thereby improving its interface charge separation properties, photocurrent, and photocatalytic activities. Our findings not only provide new members of heterometallic titanium oxide clusters to enrich the metal oxide cluster family but also open up new possibilities for their photoresponses, which may play an important role in solar energy harvesting for sustainable chemistry.
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Macromolecular Reaction Engineering
·
2022
·Vol. 16
·期 6
·2200025
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IF 1.871
Yulong Jin,Yang Yang,Changzhi Su,Junrong Wang,Yongnian Wang,Boping Liu
In this work, novel imido-Cr/silica catalysts are synthesized by modifying the Phillips catalyst CrO x /silica with isocyanates. The imido-Cr/silica, which has moderate activities of 200–300 kgPE molCr −1 bar −1 , shows lower efficiency than CrO x /silica for C 2 H 4 polymerization. On the other hand, regarding to the modified catalysts, the productivity can be improved almost linearly with increasing C 2 H 4 pressure, and very stable activities are observed during the 1 h run of C 2 H 4 polymerization. When compared with CrO x /silica, the modified catalysts can produce polyethylene (PE) with much higher molecular weight (MW) and broader molecular weight distribution (MWD), which is featured by a distinct ultrahigh MW shoulder. Meanwhile, the MW and MWD of the PE products can be reduced obviously by adding a small amount of H 2 before C 2 H 4 polymerization. In addition, it is found that more 1-hexene can be copolymerized by CrO x /silica, and it is preferentially incorporated into a portion of the PE chains. While such a preference is much less significant for the modified catalysts.
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Environmental Science-Nano
·
2021
·Vol. 8
·期 11
·3331-3342
·
IF 8.131
Dingyuan Zheng,Wenrui Yao,Ce Sun,Xiaojian Chen,Jiyuan Zhou,Baiwang Wang,Haiyan Tan,Yanhua Zhang,Yonggui Wang
Chromium (Cr(VI)) pollution poses a serious threat to the ecological environment and biological health; therefore, there is an urgent need to develop advanced technologies for Cr(VI) detection and removal. Here, a novel fluorescent wood sponge (citric acid modified wood sponge decorated with carbon dots, CA/WS-CDs) was constructed combining hierarchical porous wood sponge (WS) and carbon dots (CDs) via chemical bonding, which could simultaneously detect and remove hexavalent Cr(VI) in an aqueous medium. The chemical and physical structure of the fluorescent wood sponge was characterized, and its detection and adsorption performances for Cr(VI) were studied. The results demonstrated that the CA/WS-CDs showed excellent performance for Cr(VI) detection and removal. After being immersed in a Cr(VI) solution (50 mL, 50 mg L−1) at 25 °C for 24 h, the strong blue fluorescence of CA/WS-CDs-3 under 365 nm light weakened and fluorescence quenching started to occur, which makes the fluorescent wood sponge a detector of Cr(VI). Moreover, this novel fluorescent wood sponge had a higher adsorption ability for Cr(VI) (maximum adsorption capacity, 450.5 mg g−1), and its sorption performance met Langmuir and pseudo-second-order models. Furthermore, FTIR and XPS analysis confirmed that the hierarchical structure of the fluorescent wood sponge provided many effective sorption sites and ion transport channels, thereby guaranteeing the selective detection and efficient adsorption properties for Cr(VI). Such intriguing Cr(VI) warning and sorption performance make the proposed CA/WS-CDs hold huge prospects for practical environmental remediation.
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REACTIVE & FUNCTIONAL POLYMERS
·
2021
·
IF 3.975
Yiran Sun,Qilin Gui,Andong Zhang,Shuxian Shi,Xiaonong Chen
There are huge demands for the development of green, environmentally friendly, and easily prepared cationic adsorbents for treatment of chromium-contaminated water. In this research, we demonstrate the fabrication of a novel polyvinylamine-grafted polypropylene membrane (PPM-PVAm) for Cr(VI) adsorption. Based on a rapid two-step method, polypropylene membrane (PPM) was grafted with high biomedical safety N-vinylformamide (NVF), and then amino groups were generated via hydrolysis of the poly(N-vinylformamide) (PNVF) and these amino groups could be protonated under acidic condition as Cr(VI) adsorbing sites. The effects of both the PNVF grafting rate and its degree of hydrolysis on the adsorption performance of PPM-PVAm were investigated. The membrane with a PNVF grafting rate around 55% (wt) and a degree of hydrolysis around 70–80% exhibits the best performance for Cr(VI) adsorption under the optimal conditions, i.e. pH 2 at about 40 °C. The adsorption of Cr(VI) on PPM-PVAm matches the Langmuir model, showing a maximum Cr(VI) adsorption capacity of 208.3 mg per gram dry membrane. PPM-PVAm could be deprotonated under alkaline condition so the adsorbed Cr(VI) could be easily removed by NaOH/NaCl aqueous solution. The membrane shows excellent recycling performance, and 90.6% of the adsorption capability remains even after 10 cycles of adsorption-desorption test. Combining the unique performance and eco-friendly process in the fabrication of the membrane, PPM-PVAm shows great potential in adsorptive removal of Cr(VI) from water.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
·
IF 3.99
Yuan Tang,Xiaohong Yin,Manman Mu,Yue Jiang,Xiaoli Li,Hao Zhang,Tianwei Ouyang
A series of anatase TiO 2 @MIL-101(Cr) was synthesized using the solvothermal method for photocatalytic degradation of bisphenol A (BPA). The characterization of the composites showed that they had an octahedral shape that was similar to that of MIL-101(Cr), but the particle size was reduced to about 300–500 nm. The amount and surface area of the TiO 2 in the composites jointly influenced the photocatalytic degradation; in optimal conditions, 59 % TiO 2 @MIL-101(Cr) could achieve 99.4 % BPA degradation in 240 min under UV irradiation. This superior photocatalytic performance was the result of the effective separation of electron-hole pairs and a narrow band gap. Moreover, the optimal composite exhibited excellent stability, indicating its suitability for reuse. Reasonable pathways of BPA degradation were proposed based on the detected intermediates during the degradation, where the oxidative radical O 2 − played a dominant role.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Peng He,Jianyu Zhu,Yaozong Chen,Fang Chen,Jinglei Zhu,Mengfei Liu,Ke Zhang,Min Gan
Organic pollutants and heavy metals often coexist in wastewater, their simultaneous and effective removal from wastewater has a particular significance for environmental remediation. In this study, pyrite (FeS 2 ), the most abundant iron mineral in the Earth’s crust, was selected as a catalyst to activate persulfate for the simultaneous removal of 2,4-dichlorophenol (2,4-DCP) and Cr(VI), two common contaminants in wastewater. The results indicated that 76.2% of 2,4-DCP and 80.1% of Cr(VI) were simultaneously removed within 120 min in the pyrite/persulfate system. The simultaneous removal efficiency of 2,4-DCP and Cr(VI) by the pyrite/persulfate system was influenced by the contaminant concentration, solution pH and organic acids. The radicals SO 4 ·− and ·OH were detected as the oxidative species in the pyrite/persulfate combined system using electron spin resonance (ESR) spectroscopy, and quenching experiments with methanol and tert-butanol indicated that SO 4 ·− played a predominant role in the degradation of 2,4-DCP. The radicals (SO 4 ·− and ·OH) produced from the activation of persulfate by pyrite principally contributed to 2,4-DCP disintegration, while the removal of Cr(VI) was primarily attributed to the reduction ability of pyrite. Experiments and density functional theory (DFT) calculation results indicated that Fe is the main catalytic site, and the reductive sulfides of the pyrite surface mediated Fe 2+ recovery as donors during reaction processes. This work presented a ubiquitous natural sulfide mineral with excellent catalytic performance in the heterogeneous persulfate activation, implying a new strategy in wastewater treatment for simultaneous removal of heavy metal and organic compounds.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xiaohong Hu,Jia Wen,Haibo Zhang,Qian Wang,Caiya Yan,Lang Xing
The most important thing to do with hexavalent chromium (Cr(VI)) removal in wastewater through adsorption-reduction method is to find an adsorbent that has both strong adsorbability and reducibility. Herein, an eco-friendly material ZIF-8-EGCG, which was a combination of epicatechin gallate (EGCG) and ZIF-8, was synthesized to treat Cr(VI)-containing wastewater. At room temperature, the maximum adsorption amount of Cr(VI) reached 136.96 mg·g −1 , and the Cr(VI) reduction rate (96%) was much better than that of the original ZIF-8 (37%). Such outcome was among the best in the existing studies using MOFs to treat Cr(VI). In addition, the characterization results showed that the surface of ZIF-8-EGCG was electronegative. The material was irregular sphere with pore size of 7.12 nm and BET surface area of 113.02 m 2 ·g −1 . The well-fitted Langmuir adsorption isotherm and pseudo first/second-order kinetics model suggested that the adsorption of Cr(VI) on ZIF-8-EGCG was governed by both physical and chemical processes. Stability results revealed that the overall stability of ZIF-8-EGCG due to the etched structure was slightly inferior to ZIF-8, especially at higher temperatures (>35 °C). Simultaneously, the reaction between ZIF-8-EGCG and Cr(VI) was a spontaneous, exothermic, entropic decrease process.
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ENVIRONMENTAL RESEARCH
·
2023
·
IF 8.3
Junjun Ma,Tao E,Shuyi Yang,Liang Chen,Ying Cheng,Jia Yu,Yun Li
Stabilizing Cr(III) in tannery sludge (TS) via harmless method has always been the goal of environmental pollution treatment. In this study, a simple method to stabilize Cr(III) in TS is proposed via adding kaolin, based on the fact a large amount of organic matter contained in TS. Comprehensive characterizations confirm that kaolin can stabilize Cr(Ⅲ) via its abundant –OH and lamellar structure. Moreover, there are hydrogen bond interactions and ligand exchange-surface complexation between organic matter and kaolin, which is more conducive to form a stable ternary complex with Cr(III), in a state of organic matter-Cr(III)-kaolin. Simultaneously, the BCR sequential extraction experiment shows that the unstable water and acid soluble state of Cr(III) are reduced (from 0.61% to 0.35%), which further indicates that the stabilization of Cr(III) is successful.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Hongyi Li,Yanli Wang,Huijun Liu,Lingxu Yang,Zhengliang Liu,Chaoliu Zeng
Excellent Cr diffusion resistance and interface stability is essential for coatings applied on the surface of ferrite stainless steel interconnect for SOFCs. Four kinds of materials, the equimolar (MnFeCoNiCu) 3 O 4 (Eq), non-equimolar (Mn 0·272 Fe 0·272 Co 0·272 Ni 0·092 Cu 0.092 ) 3 O 4 (Non-Eq), MnCo 2 O 4 (MC) and the Quaternary (MnFeCoNi) 3 O 4 (Quaternary), are combined with chromium oxide to form diffusion couples in order to study the interfacial reaction mechanism. The constitutes and morphologies of the samples are tested. Two different composition reaction layers are found in equimolar/Cr 2 O 3 diffusion couple. A slight Cr inward diffusion is detected in Quaternary/Cr 2 O 3 diffusion couple.
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