CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Tianyu Yang,Yue Zhou,Jiamin Qi,Bin Li,Zewei Liu
Discharging pollutants containing toxic metal ions has become a global problem, and improper disposal of coffee grounds can also cause environmental pollution. In this work, 1T-MoS 2 @STC (Solvothermal Carbonization, STC) was prepared from coffee grounds and molybdenum disulfide by a one-step solvothermal method that is simple in operation, low in energy consumption and low in cost, which possesses efficient adsorption of Cr (VI) in wastewater. The 1T-MoS 2 @STC was characterized by SEM, TEM, XRD, XPS, Zeta potential, FTIR, and BET analyses. The results showed that MoS 2 was successfully loaded on coffee grounds. According to the pseudo-second order (R 2 = 0.99) kinetics model, chemisorption was the main cause of adsorption. The adsorption process followed the Langmuir (R 2 = 0.99) isothermal model, and the maximum adsorption capacity was 795.17 mg/g. The adsorption mechanism can be attributed to electrostatic interaction, redox reaction between Cr (VI) and active sites, and chelation between Cr (III) and hydroxyl. When 1T-MoS 2 @STC was applied to the treatment of actual water samples, the removal rate was also maintained at a high level (90%). In addition, 1T-MoS 2 @STC can maintain long-term stability (90 days) and low leaching of molybdenum (<3 mg/L) in wastewater. Therefore, in the treatment of chromium-containing wastewater, the 1T-MoS 2 @STC composite material simultaneously exhibited significant adsorption capacity, high interference resistance, stability and low leaching rate. This study provides a new efficient and stable Cr (VI) adsorbent and promotes the practical application of MoS 2 biomass derivatives composites in water purification.
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Catalysts
·
2023
·Vol. 13
·期 7
·1073
·
IF 3.9
Kaiwen Yuan,Bo Gong,Chundong Peng,Yanmei Feng,Yingmo Hu,Kai Chen,Daimei Chen,Derek Hao
Cr(VI) is a common heavy metal pollutants present in the aquatic environment, which possess toxic and carcinogenic properties. In this study, a solvothermal reaction was used to prepare porphyrin (TCPP)-modified UiO-66-NH2(UNT). The UNT integrated adsorption and photocatalytics in the application for dealing with Cr(VI). The photocatalytic reduction activities of UNT for Cr(VI) were investigated under visible light illumination. We found that the TCPP doping amount of 15 mg UNT (15-UNT) had a 10 times higher reduction rate of Cr(VI) than pristine UiO-66-NH2. The optimal 15-UNT photocatalyst demonstrated the highest photocatalytic activity, and Cr(VI) was completely removed within 80 min. In addition, the introduction of porphyrin not only enhanced the absorption of light but also enabled the transport of photogenerated electrons from porphyrin to UiO-66-NH2, which promoted the separation of charge carriers. Furthermore, the effects of factors such as porphyrin content, pH and light source on the photocatalytic reduction performances of UNT were also explored. Overall, this work presented a possible relationship between the crystal structures and the performance of UNT.Keywords:photocatalytic reduction;porphyrin;UiO-66-NH2;hexavalent chromium
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Membranes
·
2023
·Vol. 13
·期 7
·651
·
IF 4.2
Lu Liu,Hongyang Ma,Madani Khan,Benjamin S. Hsiao
To achieve high throughput, low-pressure drops, and high adsorption capacity of Cr(VI) and Pb(II) in industrial wastewater treatment, cellulose membranes containing cationic and anionic groups were fabricated, respectively. In this process, cost-effective cotton fabrics were oxidized using sodium periodate, followed by quaternary ammonium or sulfonation modifications. The chemical composition, surface morphology, and thermal and mechanical properties of the cellulose membranes were investigated by ATR-FTIR, solid-state NMR, SEM, TGA, and tensile experiments. Quaternary ammonium, aldehyde, and sulfonate groups were distributed on the cationic/anionic cellulose fibers as adsorption sites, which issue remarkable adsorption capability to the cellulose membranes. The highly toxic Cr(VI) and Pb(II) ions were used to challenge the adsorption capacity of the cationic and anionic cellulose membranes, respectively. The maximum adsorption capacities of Cr(VI) and Pb(II) ions were 61.7 and 63.7 mg/g, respectively, suggested by Langmuir isotherms, kinetics, and thermodynamics in the static experiments. The dynamic adsorption capability of cationic cellulose membranes against Cr(VI) ions was determined and compared with that of commercially available anionic-exchange membranes. Spiral wound filtration cartridges were fabricated by cationic and anionic cellulose membranes, respectively, and were used to adsorb Cr(VI) and Pb(II) from lab-made wastewater, respectively. The cationic cellulose cartridge can purify 4.4 L of wastewater containing 1.0 mg/L of Cr(VI) ions with a 100% removal ratio, while the pressure drop was retained at 246 Pa. Similarly, the anionic cellulose cartridge exhibited even more impressive adsorption capability; the removal ratio against Pb(II) was 99% when 8.6 L of 1.0 mg/L of Pb(II) ions containing wastewater was treated, and the pressure drop was retained at 234 Pa. A composite cartridge fabricated by the integration of cationic and anionic cellulose membranes was successfully employed to purify the wastewater containing Cr(VI) and Pb(II) simultaneously. The possible adsorption mechanism was proposed, and the recycling ability of the cellulose membranes was also discussed.Keywords:cationic/anionic cellulose membrane;oxidation;adsorption;heavy metal ions;wastewater treatment
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PubMed
高影响因子
Polymers
·
2022
·Vol. 14
·期 18
·3826
·
IF 4.967
Wei Mao,Renting Huang,Hao Xu,Hao Wang,Yi Huang,Shurong Huang,Jinghong Zhou
Metal-organic frameworks (MOFs) have attracted remarkable attention for their distinguished structural designability. Precisely controlling the particle size and improving the structural stability of MOF nanoparticles influence their catalytic activity significantly. In this study, six acids (nitric, hydrochloric, formic, acetic, succinic, and citric acids) were used as modulators to prepare bimetallic MIL-101 (Cr, Sn) (MIL stands for Materials of Institut Lavoisier) via a microwave-assisted hydrothermal method. Changes in volumetric, structural, stability, and catalytic properties, size, and shape of MIL-101 (Cr, Sn) were examined using scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and N2adsorption–desorption measurements. All modulators altered the MOF properties. Compared with other samples, acetic acid as a modulator mildly altered the MOF morphology by narrowing their particle size distribution, enhancing the specific surface area, and significantly improving their water and thermal stabilities. The addition of acetic acid was suitable for the catalytic conversion of glucose to 5-hydroxymethylfurfural (5-HMF), achieving a 43.1% 5-HMF yield with 91.4% glucose conversion in a mixed solution of γ-valerolactone and saturated salt water at 150 °C after 30 min.Keywords:modulators;microwave synthesis;bimetallic MIL-101 (Cr, Sn)
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2022
·
IF 7.139
Nan Xue,Yue Zhang,Chunyan Wang,Xueyan Xue,Dandan Ouyang,Hui Zhu,Jiao Yin
Currently, it is a great challenge to improve the stability of Fe-based oxygen reduction reaction (ORR) catalysts in acidic medium, because the Fenton reaction between Fe-based catalyst and H 2 O 2 will reduce the stability of the catalyst. In this study, Fe, Cr and nitrogen-doped carbon (FeCr-N-C) was synthesized via co-impregnation of biomass walnut shells with metal precursor solutions. The FeCr-N-C catalyst has an onset potential of 0.88 V vs. RHE and outperforms the Fe-N-C catalyst in acidic media. Moreover, FeCr-N-C shows negligible activity decay (ΔE 1/2 = 14 mV) in 0.1 M HClO 4 after 20 000 cycles. The experimental results proved that the bimetal synergism can produce low yield of H 2 O 2 (<2%), which might attribute to variations of local electronic structure. The reactive oxygen species of the catalyst were analyzed by Ultraviolet-visible (UV-Vis) absorption spectra . It was proved that the presence of bimetal inhibited the Fenton reaction between Fe 2+ /Fe 3+ and H 2 O 2 , and further improved the stability of the catalysts. Hence, this study proposes an efficient strategy to facilitate the practical application of Fe-based catalysts in acidic media.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2022
·
IF 6.76
Shaojie Wu,Mingyang Li,Lili Xin,Hongming Long,Xiangpeng Gao
Conventional photocatalysts for environmental applications are mainly transitional metal compounds or precious metal nanoparticles, which suffer from weak pollutant adsorption performance, thus limited their applications for high concentrated wastewaters. In this study, asynchronous cross-linked triethylenetetramine modified sodium alginate (CFTS) was used as photocatalyst for the simultaneously catalytic degradation of Cr(VI) and metronidazole (MNZ). Experimental results suggested that asynchronous cross-linking and triethylenetetramine modification have dramatically enhanced the chemical stability as well as the adsorption and photocatalytic behavior of the material. The grafted amino functional groups and cross-linked Fe 3+ ions can promote the rapid separation and transfer of electrons, thus reducing the recombination rate of photo-generated electron-hole pairs. The optimum removal rate of Cr(VI) has reached 99.5 % and MNZ can be completely removed within 20 and 30 min at pH 1.0 under UV light irradiation, respectively. The removal mechanism of Cr(VI) by CFTS is the synergistic effect of electrostatic adsorption and photocatalytic reduction, while photocatalytic oxidation dominated the degradation process of MNZ. Moreover, the removal efficiency can be enhanced in the binary solution of these two pollutants due to the utilization of photo generated electron-hole pairs, which provides new pathways in the treatment of complicated pharmaceutical and domestic sewage wastewaters.
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JOURNAL OF SOLID STATE CHEMISTRY
·
2022
·
IF 3.656
Zirui Song,Kai Guo,Wenjuan Bai,Chengchun Tang
Heavy metals in water environment do great harm to the life and health of the public and the stability of the ecological environment. Therefore, it is necessary to find an efficient solution to deal with the increasingly serious problem of heavy metal pollution. In this paper, N, N'-methylene bisacrylamide was loaded on porous boron nitride (pBN) surface with a simple synthesis method using 3-aminopropyltriethoxysilane as a coupling agent for the adsorption of Cr(VI). The prepared adsorbents were characterized with XRD , SEM, TEM , FTIR, XPS , BET, and other analytical methods. We discovered that the capacity of pBN-AS@MBA reached 83.78 mg/g, which was significantly higher than that of pBN, with an initial concentration of 20 mg/L of Cr(VI). Besides, the chemosorption of exothermic spontaneity predominated the entire process, determined from pseudo-second-order kinetics, intra-particle diffusion model, thermodynamics, and Langmuir isotherm. Not only Cr(VI) chemically react with amine groups on the sorbent , but also elicited electrostatic attractions. The reusability of sorbent was proved with a reduction rate of lower than 20%, after a few cycles of running.
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Materials
·
2022
·Vol. 15
·期 20
·7120
·
IF 3.748
Zhaojun Tan,Chuanbin Li,Lijun Wang,Mingjie Kang,Wen Wang,Mingqi Tang,Gang Li,Zaiqiang Feng,Zhenwei Yan
Hydrogen evolution reaction (HER) is one promising technique to obtain high-purity hydrogen, therefore, exploiting inexpensive and high-efficiency HER electrocatalysts is a matter of cardinal significance under the background of achieving carbon neutrality. In this paper, a hydrothermal method was used to prepare the Cr-NiC2O4/NF (Ni foam) precursor. Then, the NiO-Cr-C/NF self-supporting HER catalyst was obtained by heating the precursor at 400 °C. The catalyst presents a 3D cellular nanospheres structure which was composed of 2D nanosheets. Microstructure characterization shows that Cr and C elements were successfully doped into NiO. The results of electrochemical measurements and density functional theory (DFT) calculations show that under the synergy of Cr and C, the conductivity of NiO was improved, and the Gibbs free energy of H* (∆GH*) value is optimized. As a result, in 1.0 M KOH solution the NiO-Cr-C/NF-3 (Ni:Cr = 7:3) HER catalyst exhibits an overpotential of 69 mV and a Tafel slope of 45 mV/dec when the current density is 10 mA·cm−2. Besides, after 20 h of chronopotentiometry, the catalytic activity is basically unchanged. It is demonstrated that C and Cr co-doping on the lattice of NiO prepared by a simple hydrothermal method and subsequent heat treatment to improve the catalytic activity and stability of the non-precious metal HER catalysts in an alkaline medium is facile and efficient.Keywords:hydrogen evolution reaction;NiO;electrocatalysts;nanosphere
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高影响因子
Water
·
2022
·Vol. 14
·期 16
·2507
·
IF 3.53
Jianxin Fan,Liang Qin,Ting Duan,Zenglin Qi,Lan Zou
Biochar (BC) is considered to be a great potential adsorbent to remove various contaminants, but the sorption capacity for chromium (Cr) is predominantly limited for the net negative charge. In this study, BC from rice husk was impregnated with Mn(NO3)2solution to synthesize MnOx-modified BC (MnOBCs) for enhancing Cr(VI) removal in an aqueous solution. MnOBCs were characterized, and MnOx (manganese ore) was found to be the dominant crystal in MnOBCs. Batch sorption and kinetic experiments combined with spectral analysis were carried out to elucidate the sorption capacity and mechanisms of Cr(VI) sorption onto BC and MnOBCs. Results showed that the sorption kinetic process fitted to the Elovich model, and the modification enhanced the sorption capacity of Cr(VI) on BC. Compared to ion strength, pH is the main control factor for Cr(VI) fixed on BC and MnOBCs, and the sorption amount decreased with the pH value increasing. Moreover, X-ray photoelectron spectroscopy results showed that the proportion of Mn(II) decreased from 33.59% to 8.33%, and that of Mn(VI) increased from 30.58% to 52.72% after Cr(VI) sorption on MnOBCs. Meanwhile, the reduction reaction of Cr(VI) occurred during the sorption process on the BC and MnOBCs surface, and the reduction reaction was more obvious on the MnOBCs surface. MnOx loaded in BC can enhance the electrostatic attraction and redox capacity, which can improve the removal of Cr(VI) in an aqueous solution. This study provides information on the sorption and redox of Cr(VI) on BC, and allows us to better understand the mechanism of Cr(VI) removal in solutions by MnOBCs.Keywords:biochar;MnOx;Cr(VI);sorption;redox
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FUEL
·
2022
·
IF 8.035
Zixuan Ma,Fenghai Cao,Yuhao Yang,Liyan Wang,Tao Zhang,Minghui Tan,Guohui Yang,Yisheng Tan
Bifunctional catalysts composed of ZnCrO x oxide and ZSM-5 were widely used in syngas-to-aromatics (STA). The CO conversion on bifunctional catalysts was generally higher than that on oxide catalysts attributed to the pulling effect of zeolite, but the key factor for the improvement of CO conversion was still short of systematical explanation. In this work, the degree of nonstoichiometric spinel of ZnCrO x (ZxC) oxides was finely tuned through modulating the ratio of Zn/Cr, which could significantly influence the catalytic behaviors of ZnCrO x /ZSM-5 catalysts for the CO hydrogenation to aromatics. The increase of nonstoichiometric spinel corresponded to the increase of oxygen vacancies and the enhancement of Zn-Cr synergistic effect, which promoted the activation of H 2 and CO, leading to a dramatic increase of CO conversion. The work revealed that the action of ZnO and oxygen vacancies was the key factor for CO pulling in ZnCrO x oxide and ZSM-5 catalyzed STA reaction.
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Materials
·
2022
·Vol. 15
·期 10
·3645
·
IF 3.748
Minmin Zou,Ming Dong,Mingliang Luo,Hexin Zhu,Tian Zhao
Hierarchically porous MIL-101(Cr) (H-MIL-101(Cr)) with meso/macro-pores was directly prepared via nanofusion progress by using butyric acid as a modulating agent. In the methyl orange (MO) adsorption experiments, H-MIL-101(Cr) showed a high adsorption capability of 369.8 mg g−1, which was 1.52-fold greater than that of pristine MIL-101(Cr) (P-MIL-101(Cr)). While in the oxidation reaction of indene and 1-dodecene tests, H-MIL-101(Cr) presented much higher catalytic efficiency, with turnover frequency (TOF) values of 0.7242 mmol g−1min−1and 0.1492 mmol g−1min−1, respectively, which were 28% and 34% greater than that in the case of P-MIL-101(Cr). Thus, compared with P-MIL-101(Cr), H-MIL-101(Cr) exhibited better removal efficiency and higher levels of activity in the oxidation reactions of indene and 1-dodecene. The unique structure of H-MIL-101(Cr) also contributed to its superior performance in these processes.Keywords:hierarchically porous;MIL-101(Cr);butyric acid;MO adsorption;catalysis
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Feifan Yu,Wenkai Song,Zenglong Wu,Wenxian Chen,Jinping Cui,Yuyuan Yao
The removal of heavy metal ions from industrial effluents by molybdenum disulphide (MoS 2 ) has attracted considerable attention, but developing the removal capacity of MoS 2 toward hexavalent chromium ions (Cr(VI)) in wastewater treatment is still a challenge. Herein, a cationic polyacrylamide aerogel (CPAMA) containing -N + (CH 3 ) 3 was creatively introduced as a precursor to synthesize the CPAMA intercalated MoS 2 (MoS 2 @CPAMA). The addition of CPAMA as carrier greatly improved the dispersion and the exposure of active sites of MoS 2 , and even the -N + (CH 3 ) 3 effectively increased the surface potential of MoS 2 , which facilitated the adsorption and reduction for Cr(VI). Notably, MoS 2 @CPAMA removed 95% of Cr(VI) within 50 min and the maximum Cr(VI) removal capacity reached 800.0 mg g −1 at 400 mg L −1 , which was significantly higher than that of MoS 2 (237.1 mg g −1 ) and almost all reported MoS 2 -based materials. The results of ICP-OES and UV–vis spectrophotometer revealed that both reduction and adsorption pathway were participated during the Cr(VI) removal process, while the reduction was obviously dominated. The results of XPS showed that the -N + (CH 3 ) 3 and amide groups played a significant role in adsorbing Cr(VI) onto the MoS 2 @CPAMA surface, and the Mo was oxidized from Mo 4+ to Mo 6+ and the S 2− was oxidized into S 6+ subsequently during the reduction of Cr(VI). Interestingly, MoS 2 @CPAMA could also be used as a co-catalyst in the Fe 2+ /PMS system, and the TOC removal rate of 67% in 60 min and the retention rate of 80% for Fe 2+ were achieved. Notably, MoS 2 @CPAMA possessed high durability in the co-existing cations and anions, and the 4-CP removal rate was still as high as 94% after four consecutive cycles, indicating the splendid reusability of MoS 2 @CPAMA. This study offers new insights into the development of multifunctional MoS 2 -based materials for wastewater treatment.
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