COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
·
IF 4.9
Weiguang Zhou,Weiwei Cao,Kanghao Zheng,Lei Zhang,Shulan Shi,Yaoli Peng
Salicylhydroxamic acid (SHA) and octyl hydroxamic acid (OHA) are two commonly used hydroxamic acid-based collectors in fine cassiterite flotation . While some reports suggest that a mixture of OHA and SHA yields superior results compared to their individual use, there is a lack of experimental exploration and theoretical analysis. In this study, the flotation performance and the associated adsorption mechanism of SHA, OHA and their mixture on fine cassiterite particles was systematically investigated. The results demonstrate a synergistic effect between SHA and OHA in enhancing fine cassiterite flotation, with the most significant enhancement occurring at a 1:1 mass ratio under the natural pH conditions. This finding is corroborated by contact angle and zeta potential tests. When both SHA and OHA are present, SHA likely attaches to the cassiterite surface via chemisorption in the form of a five-membered chelate ring, while OHA adheres through physical adsorption , primarily establishing hydrogen bonds with oxygen sites on the cassiterite surface or with SHA molecules. The adsorption ratio of SHA to OHA onto cassiterite surfaces is approximately 69%: 31% when an equal mass of SHA and OHA interact with cassiterite under the natural pH condition.
研究领域:
矿物加工工程
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表面化学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Jing Tang,Xue Bai,Hongliang Huang,Songlin Xue,Jianming Pan
Simple and green synthesis of oxime or amidoxime functionalized hollow sorbents are critical for meeting the demands of highly efficient uranium extraction. To address this, a facile methodology using air bubbles generated from the “Ouzo-Like” effect as templates to synthesize oxime/amidoxime functionalized hollow PDA nanospheres (H-PDA-SO and H-PDA-AO) with fast and massive uranium extraction performances was reported. When 50 mL of Tris solution (0.6 mg mL −1 ) was mixed with n -propanol (6.25 mL) for 2.0 min, nanobubbles with the mean size of 56.7 nm spilled out, and uniformly sized H-PDA-SO nanospheres with oxime groups (about 250 nm) and H-PDA-AO nanospheres with amidoxime groups (about 150 nm) were simply obtained via self-assembled polydopamine and post-modification around the air/water interface. Owing to the accessible affinity sites and hollow structure, H-PDA-SO and H-PDA-AO displayed high maximum adsorption capacities (103.09 mg g −1 and 331.62 mg g −1 at 298 K) and fast adsorption rate (below 60 min) with high removal efficiency. Under the influence of coexisting ions, H-PDA-SO and H-PDA-AO showed not only a high uranium adsorption capacity but also a more predominant capacity than all the competing ions. Moreover, H-PDA-SO and H-PDA-AO exhibited high stability as well as excellent recyclability toward uranium capture after five regeneration cycles. Surface coordination of oxime/amidoxime sites with uranium was the main binding mechanism, and negative charged O-containing function groups enhance this affinity interactions.
研究领域:
材料科学
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环境化学
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纳米技术
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放射化学
✓ 已验证
产品关联
DOI
高影响因子
Royal Society Open Science
·
2018
·Vol. 5
·期 8
·
IF 2.504
Liuyi Ren,Hang Qiu,Wenqing Qin,Ming Zhang,Yubiao Li,Penggang Wei
The existence of metal ions should not be ignored in both hydrometallurgy and flotation. In this study, the effects of Ca2+, Mg2+ and Fe3+ on the flotation performance of cassiterite using octanohydroxamic acid (OHA) as the collector were investigated by micro-flotation tests, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, contact angle, zeta (ζ) potential measurements and atomic force microscopy (AFM) imaging. The results of the flotation and contact angle experiments showed that the addition of Ca2+, Mg2+ and Fe3+ significantly decreased both the recovery and contact angle of cassiterite with pH ranged from 6.0 to 12.0 in the presence of OHA collector. ζ-Potential measurements, solution chemistry analysis and FTIR measurements indicated that the flotation recovery of the cassiterite declined due to the CaOH+, MgOH+ and Fe(OH)3 sites on the cassiterite surface. XPS results indicated that the chemisorption of OHA and calcium ions on the cassiterite surface finally changed its chemical properties. The AFM images also revealed that new species Fe(OH)3 of Fe3+ formed and adsorbed on the cassiterite surface at pH 9.0. The adsorption of Fe(OH)3 reduced the adsorption of OHA on the cassiterite surface, thus the hydrophobicity of cassiterite was deteriorated.
研究领域:
矿物加工工程
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表面化学
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产品关联
DOI
PubMed
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2021
·
IF 3.493
Zhiji Chen,Feiying Mao,Haoteng Zheng,Qinjie Xiao,Zhihao Ding,Anming Wang,Xiaolin Pei
Aromatic nitriles are important structural motifs that frequently existed in pharmaceutical drugs. Due to the convenient synthesis of aldoximes from aldehydes, the dehydration of aldoximes to corresponding nitriles by aldoxime dehydratases (Oxds) is considered as a safe and robust enzymatic production route. Although the Oxd genes are widely distributed in microbial kingdom, so far less than ten Oxds were expressed and further characterized. In this study, we found 26 predicted putative Oxd genes from the GenBank database using a genome mining strategy. The Oxd gene from Pseudomonas putida F1 was cloned and functionally expressed in Escherichia coli BL21 (DE3). The amino acid sequence of OxdF1 shows high identities of 33∼85 % to other characterized Oxds, and contained a ferrous heme as the catalytic site. The optimum reaction pH and temperature of recombinant OxdF1 were 7.0 and 35 °C, respectively. OxdF1 was stable in pH 7.0 potassium phosphate buffer at 30 °C, and its half-life was approximately 3.8 h. OxdF1 can efficiently dehydrate aromatic and heterocyclic aldoximes to nitriles, such as 2-bromobenzaldoxime, 2-chloro-6-fluorobenzaldoxime, thiophene-2-carboxaldoxime, and pyridine-3-aldoxime. Therefore, the recombinant OxdF1 shows a potential application in the cyanide-free synthesis of aromatic nitriles.
研究领域:
生物化学
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酶学
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药物化学
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生物技术
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DOI
PubMed
高影响因子
EUROPEAN POLYMER JOURNAL
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2022
·
IF 5.546
Lei Du,Zhenzhen Liu,Zhixiong Ye,Xiaolong Hao,Rongxian Ou,Tao Liu,Qingwen Wang
Polyurethane hot-melt adhesives (PU-HMAs) have been widely used due to their outstanding advantages, however, the high dependence on non-renewable petrochemical resources has limited their green and sustainable development. It is still a challenge to achieve high adhesive strength and high biomass content of PU-HMAs simultaneously. Herein, a bio-based dynamically cross-linked polyurethane hot-melt adhesive (DPU) was constructed by the bio-based vanillin oxime (VO) and soybean oil polyol (SBOH), along with polytetrahydrofuran (PTMG) and isophorone diisocyanate (IPDI). The highest lap shear strength of the DPU adhesive reached up to 6.55 ± 0.88 MPa only after 30 min curing, while the biomass content reached 25 wt% of the total mass, which is significantly higher than that of previous reports. Especially, the oxime group of VO reacts with isocyanates to form the reversible oxime-carbamate covalent bonds, which endows the adhesive with excellent self-healing and repeatable adhesion properties. The lap shear strength remained at 5.56 ± 0.89 MPa after 7 complete breaking-repairing cycles, which exceeded 80 % of the initial lap shear strength. Moreover, the DPU adhesive also displayed excellent resistance to low temperatures and solvents, and better adaptability on different substrate surfaces than commercial PU-HMA Lubrizol-5173 and Loctite-3542. Therefore, this work provided a new route for developing high-performance and self-healing bio-based PU-HMAs.
研究领域:
材料科学
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绿色化学
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产品关联
DOI
高影响因子
Nanoscale
·
2020
·Vol. 12
·期 20
·11267-11279
·
IF 6.895
Hongkai Zhao,Xiaoxia Li,Mingyue Zheng,Xian Zhao,Qun Zhang,Yi Luo,Weiliu Fan
The construction of both highly efficient and stable hybrid artificial photosynthetic systems comprising semiconductors as photosensitizers and abundant metal-based molecular complexes as cocatalysts for photocatalytic H2 generation remains challenging. Herein, we report an effective and stable CdS/cobaloxime hybrid system prepared by inserting an amorphous TiO2 (a-TiO2) interlayer with adjustable thickness and by covalently-surface-attaching molecular cobaloxime catalysts. This hybrid system displayed outstanding photocatalytic H2 production and reached a maximum rate of ∼25 mmol g−1 h−1, which was ∼20.8 times that of pure CdS and 1.7 times that of the CdS/cobaloxime system without an a-TiO2 interlayer (CdS/Co). More importantly, 6 nm a-TiO2 uniformly coated CdS nanorods (CdS NRs) exhibited exceptional 200 h long-term catalytic behaviour under ≥420 nm visible light irradiation. However, the H2 production performance of the CdS/Co hybrid system decreased significantly over 10 h. Density functional theory (DFT) calculations indicated that the a-TiO2 surface can provide abundant bonding sites for the effective immobilization of molecular catalysts. Moreover, Mott–Schottky electrochemical measurements and femtosecond transient absorption spectroscopy revealed that the a-TiO2 interlayer had favourable band levels that could fasten the photoexcited electron transfer from CdS to molecular cobaloxime and could extract holes with intraband electronic states generated by defects, thus prohibiting CdS photocorrosion and improving the stability of the hybrid system. This study proposes a strategy for designing multifunctional interlayers for the effective immobilization of molecular catalysts, beneficial regulation of photoinduced charge carriers, and improvement of the stability as well as facilitation of the construction of artificial photosynthetic hybrid systems with high efficiency and durability.
研究领域:
材料科学
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光化学
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能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Wenqi Zhang,Cong Liu,Xiangrui Meng,Jie Sun,Huayu Tian
The preparation of adsorbents with low cost, efficient adsorption and high profitability for gold recovery has important practical applications. In this work, synergistic poly (imine dioxime and amidoxime) (PDA) adsorbents were successfully prepared for gold recovery. An inexpensive engineering polyacrylonitrile (PAN) fiber is selected as the adsorbent substrate covalent binding with hydroxylamine hydrochloride to obtain PDA. The PDA surface with imine dioxime and amidoxime groups has a rich charge density and is more easily combined with gold ions through electrostatic interactions. The adsorption process of gold on PDA is a spontaneous endothermic process with monomolecular layer adsorption and the adsorption capacity increases with the increasing temperature under acidic conditions. The maximum adsorption capacity of PDA can reach 2937 mg g −1 at 25 °C and pH = 2 with an equilibrium time of 168 h. Meanwhile, excellent gold adsorption performance is also observed for PDA in simulated water treatment filler and water circulation reactor as well as interference conditions with other metal ions. Surprisingly, PDA has an ultra-low preparation cost ($ 2.54 × 10 2 kg −1 ), yet enables high-value gold (2.9 kg) for every kilogram of PDA with significant economic benefits. Therefore, this work will provide new ideas for the development of inexpensive, highly efficient, and specialized adsorbent preparation for gold recovery.
研究领域:
材料科学
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环境工程
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化学工程
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冶金学
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产品关联
DOI
高影响因子
Chem Catalysis
·
2022
·
IF 0
Xianhao Zhang,Huijuan Jing,Shiming Chen,Bing Liu,Liang Yu,Jianping Xiao,Dehui Deng
Summary Cyclohexanone oxime (CHO), a key C=N organic compound in the manufacture of nylon 6, is conventionally synthesized via a multistep process that consumes expensive NH 3 and H 2 under harsh conditions. Herein, we report the direct electro-synthesis of CHO from low-cost NO, H 2 O, and cyclohexanone over a carbon catalyst under ambient conditions. A high Faradaic efficiency of 44.8% and a formation rate of 10.7 mg cm −2 h −1 for CHO were achieved at −0.4 V versus the reversible hydrogen electrode through optimizing the surface hydrophobicity of the catalyst to facilitate diffusion of reactants. Controlled experiments and 15 N-labeling tests verified that the nitrogen in the CHO product originates from NO. Density functional theory calculations showed that the armchair edge of carbon could be the active site with a reaction mechanism following NO → NO∗ → HNO∗ → HNOH∗ → NH 2 OH → CHO. This work suggests a direct, green, and low-cost synthesis strategy for high-value CHO from pollutant NO.
研究领域:
化学工程
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环境科学
✓ 已验证
DOI
Polymers
·
2020
·Vol. 12
·期 9
·1905
·
IF 3.426
Xiaoyan Cao,Qing Wang,Shuai Wang,Ruilin Man
In this study, a novel polystyrene-poly(hydroxamic acid) copolymer was synthesized as an effective adsorbent for the treatment of rare earth elements. Through the use of elemental analysis as well as FTIR, SEM, XPS, and Brunauer-Emmett-Teller (BET) surface area measurement, the synthesized polymer was found to have a specific surface area of 111.4 m2·g−1. The adsorption performances of rare metal ions were investigated under different pH levels, contact times, initial concentrations of rare earth ions, and temperatures. The adsorption equilibrium for La3+, Ce3+, and Y3+onto a polystyrene-poly(hydroxamic acid) copolymer is described by the Langmuir model, which confirms the applicability of monolayer coverage of rare earth ions onto a polystyrene-poly(hydroxamic acid) copolymer. The amount of adsorption capacities for La3+, Ce3+, and Y3+reached 1.27, 1.53, and 1.83 mmol·g−1within four hours, respectively. The adsorption process was controlled by liquid film diffusion, particle diffusion, and chemical reaction simultaneously. The thermodynamic parameters, including the change of Gibbs free energy (∆G), the change of enthalpy (∆H), and the change of entropy (∆S), were determined. The results indicate that the adsorption of resins for La3+, Ce3+and Y3+was spontaneous and endothermic. The polymer was also used as a recyclable adsorbent by the desorption experiment.Keywords:adsorption;hydroxamic acid resin;rare earth ions;separation;synthesis
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Zhiquan Li,Xiucheng Zou,Guigang Zhu,Xiaoya Liu,Ren Liu
Developing efficient unimolecular visible light-emitting diode (LED) light photoinitiators (PIs) with photobleaching capability, which are essential for various biomedical applications and photopolymerization of thick materials, remains a great challenge. Herein, we demonstrate the synthesis of a series of novel PIs, containing coumarin moieties as chromophores and oxime ester groups as initiation functionalities and explore their structure–activity relationship. The investigated oxime esters can effectively induce acrylates and thiol-based click photopolymerization under 450 nm visible LED light irradiation. The initiator O-3 exhibited excellent photobleaching capability and enabled photopolymerization of thick materials (∼4.8 mm). The efficient unimolecular photobleachable initiators show great potential in dental materials and 3D printings.
研究领域:
材料科学
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化学
·
生物医学工程
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Haiyan Luo,Haoyu Yao,Min Li,Fanfang Meng,Hui Zhao,Changjiang Yu,Xiangfeng Liang,Huizhou Liu
Efficient extraction of uranium from seawater is of great significance to the stable development of nuclear energy. The graft modification of pectin is expected to realize the efficient extraction of uranium through the dual action of aminoxime and carboxyl groups. In this work, novel biomimetic pectin adsorbents were developed and their performance on the adsorption performance of uranium from seawater was investigated. The physical structure and morphology were characterized by employing FT-IR, BET, SEM and elemental analysis. The skeleton structure and surface functional groups of the pectin-derived adsorbents, which were modified to improve the adsorption selectivity, favored the adsorption of uranium in simulated seawater. The modified apple pectin (MPA) adsorbents exhibited the highest adsorption capacity of 212.27 mg/g at optimal conditions. The thermodynamic results showed that the adsorption of uranium on MPA surface followed the Langmuir single-layer model, and the theoretical maximum adsorption capacity could reach up to 296.25 mg/g. The adsorption process conformed to the pseudo-second-order model. Furthermore, the synergistic mechanism between aminoxime and carboxyl groups of the pectin-based adsorbents was proposed. In conclusion, this work provides a new bio-based adsorbent with high efficiency for uranium extraction from concentrated seawater.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2017
·
IF 2.625
Yuxing Xu,Taifeng Liu,Heng Yin,Tingting Yao,Xiuli Wang,Hongxian Han,Can Li
Better understanding the multi-electron transfer processes in photocatalytic water splitting and CO 2 reduction is crucial for the development of the efficient artificial photosynthesis systems for production of solar fuels. Here, the multi-electron transfer from TiO 2 to cobaloxime (a molecular catalyst) in cobaloxime/TiO 2 hybrid systems has been studied in detail in the presence of methanol. The results of the thermodynamic study revealed that simultaneous two-electron transfer from TiO 2 to cobaloxime is the most plausible account for the interpretation of the observed photocatalytic activities . And the accumulation of photogenerated electrons in TiO 2 is an essential prerequisite for simultaneous two-electron transfer from semiconductor to the molecular catalyst based on the analysis of charge transfer processes.
研究领域:
化学
·
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）