Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Kai He,Yuanfang Lai,Shuchen Wang,Jie Hong,Xianliang Huang
The application of sodium sulfide (Na 2 S) as sulfidation reagent of zero valent iron (ZVI) has been well studied, however, the effect of Na 2 S existence on ZVI reactivity remains obscure. In this study, Ni(II) removal performance, mechanism, and stability by ZVI with Na 2 S were investigated at neutral condition. The results showed that Ni(II) removal sharply increased from < 5–100% by ZVI within 60 min with the increase of Na 2 S concentration, but the subsequent Ni(II) release occurred. In addition to the slight Ni(II) removal by Na 2 S in aqueous phase , Ni(II) was mainly removed by the adsorption and reduction by Na 2 S mediated ZVI system. Characterization analysis indicated that Na 2 S could lead to the severe Fe 0 corrosion and the main corrosion product on ZVI was lepidocrocite , which played the dominant role for Ni(II) immobilization. Meanwhile, the formation of iron sulfides on ZVI surface would enhance Ni(II) reduction and partially transform the adsorbed Ni(II) to NiS. Moreover, the higher ionic strength could further enhance the initial Ni(II) removal rate but the stability became poor. Regardless of the additive methods , the Ni(II) removal significantly enhanced in the system of ZVI and Na 2 S combination. Overall, this work reveals the sulfide mediated Fe 0 corrosion and provides a potential method for enhancing the reactivity of ZVI in the treatment of Ni(II) pollution.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Jizhi Zhou,Pei Liu,Zeyuan Liu,Jia Zhang,Xin Huang
The recovery of phosphorus (P) from wastewater has attracted substantial attention with the atrophy of global P resource. In the current work, the simultaneous recovery of P with the removal of nickel (Ni) via iron/activated carbon (Fe/AC) and hydrogen peroxide (H 2 O 2 ) form nickel-plating wastewater was achieved. The isotherm reaction showed a maximum P recovery of 99.99% with an equilibrium concentration of P of 0.12 mg/L, which was lower than the limitation of discharge regulation (China national regulation, 0.5 mg/L). The optimal conditions for P recovery were 0.25 mol/L H 2 O 2 , a Fe/AC mass ratio of 1:1, an at 60 °C, which led to the ratio of P in the form of FePO 4 in the residue to be 77%. Moreover, the Fe/AC microelectrolysis coupling to H 2 O 2 promoted Fe 2+ production from Fe 0 and improved the circulation of Fe 2+ , which improved the production of hydroxyl radicals with increasing pH and consequently enhanced oxidation efficiency of hypophosphite. The FePO 4 was found the major form of phosphate in the precipitate. The highest removal rate of nickel was 89%, which was attributed to its precipitation at high pH and adsorption on to iron hydroxides and activated carbon. Nickel purification was achieved by further coagulation as the equilibrium concentration of Ni was lower than 0.1 mg/L. Therefore, our work provides a promising approach for simultaneous recovery of P and removal of Ni from electroplating wastewater.
研究领域:
环境科学
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化学工程
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Xuefeng Xiao,Yongjun Sun,Jianwen Liu,Huaili Zheng
Two bioflocculants of starch-graft-P[acrylamide-acrylic acid] (SAA) and starch-graft-P[acrylamide-2-acacrylamido-2-methyl-1-propanesulfonic acid] (SAS) are designed for the flocculation–chelation of heavy metals. The successful polymer synthesis is confirmed through physicochemical characterization. SAA and SAS are used to remove Cu(II), Zn(II), and Ni(II) from simulated wastewater and Ni(II) from actual electroplating wastewater. The removal efficiencies for Cu(II), Zn(II), and Ni(II) in the simulated wastewater by SAA and SAS are more than 80.00%, whereas those for Ni(II) are more than 90.0% in the Ni-containing electroplating wastewater at the optimal condition. Flocculation experiments reveal that the sulfonate structure of SAS is highly conducive to improve flocculation efficiency. SAA and SAS have high selectivities for Cu(II) in the simulated water sample with mixed heavy metal. Finally, the 3E (i.e., environmental impact, economic benefit, and energy consumption) triangular evaluation model is established to evaluate the flocculation experiments for the removal of heavy metal ions using SAA and SAS.
研究领域:
环境科学
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材料科学
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高影响因子
Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Yuzhu Xue,Weinan Wang,Yanhong Zhang,Qinhua Fan,Ying Zhang,Chen Ling,Yuwei Pan
This study proposes a green purification strategy in which mild decomplexation of Ni-EDTA into other Ni complexes facilitates the efficient removal and recovery of nickel through resin adsorption. Decomplexation of Ni-EDTA by boron/Fe 2+ /H 2 O 2 (B/Fe 2+ /H 2 O 2 ) followed by resins adsorption was conducted for Ni(II) removal in Ni-EDTA. The Ni(II) removal efficiency could only achieve 1.3 % and 6.2 % while Ni(II) coexisted with EDTA but more than 10 times of higher when Ni(II) coexisted with EDTA-relatives via the single adsorption of commercial heavy metal-affined resins (D001 and D463), which attributed to the increased binding energies of these Ni-EDTA’s degradation products complexes than Ni-EDTA based on density functional theory (DFT) calculation. In comparing to precipitation, the resin adsorption required much less mineralization of EDTA to have a better removal efficiency of Ni(II). B improved the efficiency of Ni-EDTA decompexation by accelerating the recycle of Fe 3+ /Fe 2+ . The EDTA (and TOC) removal enhanced from 48.7 % (4.7 %) to 94.7 % (11.9 %) by B/Fe 2+ /H 2 O 2 process comparing to Fe 2+ /H 2 O 2 process. With the high EDTA but low TOC removal efficiency after B/Fe 2+ /H 2 O 2 treatment, Ni(II) removal efficiency via resins adsorption could maximum achieve 80.5 %, 2–3 times of that via regular precipitation method. In addition, B and resins exhibited good reusability in five cycles, and B/Fe 2+ /H 2 O 2 -resins process had excellent adaptability to different heavy metal complexes. B/Fe 2+ /H 2 O 2 -D463 system not only could reduce 78.4 % reagents cost compared with that of Fe 2+ /H 2 O 2 -precipitation process, but also could save much cost than other processes. The results provide new insights for the cost-effective treatment of EDTA-complexed heavy metal wastewater.
研究领域:
环境科学
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化学工程
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高影响因子
FUEL
·
2019
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IF 5.128
Tong Geng,Hui Chen,Jun Xu,Mannian Ren,Jichang Liu,Fahai Cao
Nickel in crude oil deactivates hydrocracking catalysts, which imposes adverse effects on the subsequent processing of crude oil. However, the commonly used acidic agents always corrode the processing equipment, and phosphoric agents often introduce in extra pollutions. Therefore, an efficient and environmentally friendly nickel removal agent is urgently needed. In this work, micro-sized SiO 2 coated by poly( N -vinyl pyrrolidone) (PVP) (PVP@SiO 2 -C) and grafted by PVP (PVP@SiO 2 -G) are prepared and characterized by FT-IR, TGA, elemental analysis, SEM and TEM. Both of core-shell particles exhibit excellent nickel removal rate for crude oil. The influences of particle concentration, electric desalting temperature and oil/water ratio on nickel removal rate are further studied. It is found that, when the concentration is lower than 4000 ppm, the nickel removal rate increases with increasing particle concentration. Appropriate temperature and oil/water ratio benefit for the removal of nickel. Since the PVP@SiO 2 -G exhibits a much better nickel chelating ability than PVP@SiO 2 -C, the nickel removal rate of PVP@SiO 2 -G reaches as high as 64.4%. In addition, PVP@SiO 2 -G also shows a favorable removal selectivity for nickel at low calcium concentrations. These results indicate that core-shell particles PVP@SiO 2 -G have great potential for nickel removal from crude oil to water.
研究领域:
化学工程
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环境科学
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高影响因子
FUEL
·
2023
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IF 7.4
Kaili Shen,Lingrui Cui,Lianzhou Yang,Xingguo Wei,Xu Liu,Mannian Ren,Fahai Cao,Jun Xu
Nickel in crude oil adversely affects the refining process for rapidly deactivating the hydrogenation and cracking catalysts. Polymer brushes bearing high-density ligands have shown promising nickel removal ability. In this work, submicron polybutadiene (PB) grafted by polyacrylamide (PAM@PB) was prepared and characterized by the transmission electron microscope, dynamic light scattering, and elemental analysis, which was also compared with the PB latex grafted by polyacrylic acid (PAA@PB) synthesized in our previous work. The nickel removal rates by both brushes were evaluated through the electric desalination process. The results show that the nickel removal capacity of PAA@PB is higher than that of PAM@PB. By the molecular dynamics simulations, the stretching and competitive chelation of polymer brush models PAA@PB-M and PAM@PB-M were investigated. Charged polyacrylic acid brushes usually have a higher thickness layer and a lower ligand density under the electrostatic repulsion and hydrogen bonding. The electrostatic interaction plays a more important role than the van der Waals interactions on nickel removal. PAA@PB-M is more attractive against Ni 2+ ions than PAM@PB-M. The inevitable formation of stable sandwiched π-π stacking structures between Ni 2+ ions and multiple porphyrin rings causes great difficulty in nickel removal during the electric desalination process. Adding protons to the oil phase can reduce the formation of the sandwiched structures and further improve nickel removal rates. In this paper, molecular dynamics simulation is innovatively applied to the mechanism of demetallization of polymer brushes, revealing the differences in structure and demetallization between charged and neutral polymer brushes, which provides guidance for the design of core–shell polymer brushes with high demetallization efficiency.
研究领域:
化学工程
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材料科学
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2022
·Vol. 139
·期 31
·e52709
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IF 3.057
Lianzhou Yang,Kaili Shen,Jun Xu,Mannian Ren,Fahai Cao
Stable oil-soluble metals complexes in crude oil bring various problems to the oil processing. In the previous work, four spherical polymer brushes with SiO 2 as a core showed high nickel and calcium removal efficiency, but SiO 2 has high density and smaller specific surface area, greatly limiting the demetallization efficiency. In the present work, spherical polyelectrolyte brushes (PAA@PB) were synthesized by emulsion grafting polymerization. DLS and TEM show that PAA@PB exhibits a uniform spherical core-shell structure with a diameter of 526.3 nm, and TGA exhibits that the grafting rate is 20.6%. The demetallization rate and selectivity of PAA@PB were investigated with varying concentration, electrical desalination conditions, pH value, and NaCl concentration. In contrast, the demetallization efficiency of PAA@PB is much greater than that of PAA@SiO 2 -G. Notably, PAA@PB exhibits excellent nickel removal efficiency, but a little more selective for iron. The optimal removal rate for calcium, nickel, and iron are 55.3%, 52.6%, and 46.1%, respectively. Compared with P4VP@SiO 2 -G, which possesses the highest demetallization efficiency among four polymer brushes with SiO 2 , to achieve the same nickel removal rate, the concentration of PAA@PB is almost eight times less than that of P4VP@SiO 2 -G. Consequently, PAA@PB has great potential as an excellent comprehensive demetallization agent.
研究领域:
化学工程
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材料科学
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高影响因子
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