APPLIED SURFACE SCIENCE
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2024
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IF 6.3
Song Ningbo,Yin Wanzhong,Xie Yu,Yao Jin
Using seawater for mineral flotation conserves fresh water resources and offers significant environmental and economic benefits. However, the adverse effect of seawater restricts its application in mineral flotation. The regulators can eliminate the adverse effect caused by seawater during flotation separation of lead and copper. In this paper, the flotation separation of galena and chalcopyrite in seawater was tested. Compared with those in deionized water, the lead grade of concentrate in seawater flotation declined from 50.10% to 48.90%. Meanwhile, the recovery of galena declined from 74.33% to 60.58% and the SI value declined from 1.565 to 1.324. With the addition of SHMP (sodium hexametaphosphate), SS (sodium silicate) and EDTA (ethylenediamine tetraacetic acid), the SI value increased from 1.324 to 1.923, 2.002 and 1.939, respectively. Noteworthy, when EDTA was excessive, the grade of Pb was 60.80%, the recovery of galena was 60.86% and the SI value was 2.113. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Atomic force microscopy, Density functional theory calculation and E-DLVO calculation verified the micro-flotation results and revealed the mechanism of action.
研究领域:
矿物加工工程
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环境科学
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DOI
高影响因子
WATER AIR AND SOIL POLLUTION
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2026
·Vol. 237
·期 12
·717
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IF 3.5
Luo Yuwen,Jiang Qingxi,Zhang Hualin,Qi Shuangxing,Zen Yuanlai,Peng Chenliang,Wang Guanshi
The extensive use of ammonium sulfate as a leaching agent in the mining process of ion-adsorption rare earth ores (IAREO) has led to severe pollution of ammonia nitrogen in the wastewater of historical residual ores. In this study, natural clinoptilolite was modified using sodium hexametaphosphate (SHMP) to elucidate both the enhanced adsorption performance and the fundamental mechanisms governing NH 4 + removal. Single-factor experiments identified the optimal modification conditions as an SHMP concentration of 0.1 mol·L −1 , a temperature of 80 °C, and a duration of 3 h, under which the NH 4 + adsorption capacity of modified clinoptilolite increased to 2.6 times that of the natural clinoptilolite. Characterization using SEM, BET, XRD, and FTIR revealed that SHMP treatment increased surface roughness and enhanced pore structure without altering the crystalline framework. Adsorption experiments demonstrated that NH 4 + adsorption onto the modified material conformed to the pseudo-second-order kinetic model and the Langmuir isotherm, yielding a maximum adsorption capacity of 16.72 mg·g −1 , indicating a chemisorption-dominated process characterized by spontaneous, exothermic monolayer adsorption . Ion exchange was proven as the primary mechanism, with NH 4 + replacing Na + in the clinoptilolite structure, while coexisting cations such as K + and Ca 2+ markedly inhibited adsorption. Additionally, the modified clinoptilolite exhibited substantial removal efficiency when applied to actual wastewater from IAREO operations. Overall, the findings demonstrate the effectiveness of SHMP-modified clinoptilolite and provide guidance for ammonia–nitrogen remediation in IAREO sites.
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高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2024
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IF 5.3
Xiaomin Ma,Pengcheng Wen,Yuping Fan,Wei Sun,Xianshu Dong,Maoqing Yang,Liayong He,Yuanpeng Fu
The objective of this study was to elucidate the cooperative modification mechanism of anionic composite pharmaceuticals on coal substrates. Composite pharmaceuticals were synthesized using sodium hexametaphosphate (SHMP) and sodium polycarboxylate to reduce coal hygroscopicity. The mesoscopic alteration process between the coal surfaces and the compound pharmaceuticals was examined via atomic force microscopy (AFM). AFM showed that SHMP was multilayer-adsorbed on coal via electrostatic and hydrogen bonding, while sodium polycarboxylate was single layer-adsorbed at the SHMP layer via electrostatic interactions. Composite pharmaceutical adhesion to coal was lower than that for individual pharmaceuticals, indicating synergistic effects. The mechanism underpinning the microscopic synergistic effect of complex pharmaceuticals on the coal surface was further examined using density functional theory (DFT) at the molecular scale. DFT calculations showed that the adsorption energy of SHMP binding to a sodium polycarboxylate molecule was greater than that of SHMP binding to two identical pharmaceutical molecules. The SHMP portion generally interacted with the aromatic coal nucleus via its ring structure, exposing the sodium polycarboxylate carbon chain to maximize the adsorption energy. Combining DFT and AFM provided insight into the composite pharmaceutical function, and a theoretical framework for coal flotation separation was established.
研究领域:
材料科学
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化学工程
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分子模拟
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Zhangchao Mo,Xuesong Jiang,Xiaoxiao Zhu,Juxuan Ding,Boyuan Ban,Jifei Sun,Jian Chen
Glass fiber powder contains two distinct forms: crumb-shaped and rod-shaped glass fiber powder particles. The shape and size of the particles in glass fiber powder have a great influence on its application. In order to separate rod-shaped glass fiber, the effects of different dispersants, such as SHMP, NaOL, and Na 2 SiO 3 on them were investigated by settling experiments. Zeta potential, X-ray photoelectron spectroscopy (XPS), optical microscope, and other methods were used to analyze the adsorption behavior and settling mechanism. Three-point bending experiment and dynamic mechanical analysis (DMA) were used to evaluate the performance of epoxy resin composites reinforced with the raw glass fiber powder and the rod-shaped glass fiber powder. The results show that SHMP can effectively separate crumb-shaped glass fiber powder and rod-shaped glass fiber powder, leading to a notable increase in sedimentation recovery difference, up to Δ=51.08 %. A preferential sedimentation separation mechanism is proposed to elucidate the settling mechanism. When the content of glass fiber powder and rod-shaped glass fiber is 5 %, the glass transition temperature shifts significantly towards higher values, leading to the optimum comprehensive mechanical properties of the composites. Compared with the original epoxy resin, the flexural strength increased by 10.38 % to 95.18 MPa and by 20.11 % to 103.57 MPa. Similarly, the storage modulus increased by 14.14 % to 2083 MPa and by 21.64 % to 2220 MPa.
研究领域:
材料科学
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复合材料
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高分子科学
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机械工程
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DOI
高影响因子
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