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Stabilization/solidification mechanisms of tin tailings and fuming slag-based geopolymers for different heavy metals

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 43-55页

作者： xian zhou Zhengfu Zhang Hui Yang School of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China Kunming Metallurgical Research Institute Co. Ltd.Kunming650031China

Tin mine tailings(TMT)and fuming slag(FS)contain many heavy metals(As,Cr,Cu,Zn and Mn)that cause severe pollution to the environment.Herein,geopolymers were prepared using TMT,FS and flue gas desulfurization gypsum(FGDG)to immobilize heavy metals,and their compressive strength and heavy metal leaching toxicity were investigated.It was first determined that T4F5(TMT:FS=4:5)sample exhibited the highest compressive strength(7.83 MPa).T4F5 achieved 95%immobilization efficiency for As and Cr,and nearly 100%for Cu,Zn and Mn,showing good immobilization performance.A series of characterization analyses showed that heavy metal cations can balance the charge in the geopolymer and replace Al in the geopolymer structure to form covalent bonds.In addition,about 2%–20%of heavy metal Fe was immobilized in hydration products,heavy metal hydroxides and non-bridging Si–O and Al–O coordination with silica-aluminate matrices.AsO33−was oxidized into AsO43−,which may form Ca–As or Fe–As precipitates.Cr2O72−was converted to CrO42−under alkaline environment and then combined with OH−to form Cr(OH)3 precipitates.Mn2+may react directly with dissolved silicate to form Mn2SiO4 and also form Mn(OH)2 precipitates.The unstable Mn(OH)2 can be further oxidized to MnO2.The heavy metal cations were immobilized in the silicoaluminate lattice,while the anions tended to form insoluble precipitates.These results may benefit the industry and government for better handling of TMT,FS and solid wastes containing the abovementioned five heavy metals.

关键词： Heavy metals Cementitious materials Tin tailings Stabilization/solidification Redox

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Highly efficient recovery of waste LiNi_(x)Co_(y)Mn_(z)O_(2) cathode materials using a process involving pyrometallurgy and hydrometallurgy

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 149-160页

作者： Tianwei Zhang Juanye Dao Jinsong Wang Yuzhong Guo Rundong Wan Chengping Li xian zhou Zhengfu Zhang Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China

Substantial environmental and economic benefits can be achieved by recycling used lithium-ion batteries. Hydrometallurgy is often employed to recover waste LiNi_(x)Co_(y)Mn_(z)O_(2) cathode materials. As Ni, Co and Mn are transition metals, they exhibit similar properties;therefore, separating them is difficult. Thus, most researchers have focused on leaching processes, while minimal attention has been devoted to the separation of valuable metals from waste LiNi_(x)Co_(y)Mn_(z)O_(2) cathode materials. Herein, we propose an environment-friendly, gentle process involving the usage of pyrometallurgy and hydrometallurgy to gradually leach valuable metals and effectively separate them. Interestingly, Li is recovered through a reduction roasting and water leaching process using natural graphite powder, Ni and Co are recovered through ammonia leaching and extraction processes and Mn is recovered through acid leaching and evaporation–crystallization processes. Results show that ~87% Li, 97.01% Co, 97.08% Ni and 99% Mn can be leached using water, ammonia and acid leaching processes. The result obtained using the response surface methodology shows that the concentration of (NH4)2SO3 is a notable factor affecting the leaching of transition metals. Under optimal conditions, ~97.01% Co, 97.08% Ni and 0.64% Mn can be leached out. The decomposition of LiNi_(x)Co_(y)Mn_(z)O_(2) is a two-step process. This study provides valuable insights to develop an environment-friendly, gentle leaching process for efficiently recycling valuable metals, which is vital for the lithium-ion battery recycling industry.

关键词： Waste LiNixCoyMnzO2 cathode materials Leaching Effective separation Series process

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Quasi-shadowing for Z^(d)-actions

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1563-1580页

作者： Juan PAN xian Kun REN Yun Hua zhou School of Mathematics and Statistics Chongqing Technology and Business UniversityChongqing 400067P.R.China College of Mathematics and Statistics Chongqing UniversityChongqing 401331P.R.China

A diffeomorphism is non-uniformly partially hyperbolic if it preserves an ergodic measure with at least one zero Lyapunov exponent.We prove that a C^(1)-smooth Z^(d)-action has the quasishadowing property if one of th... 详细信息

关键词： Quasi-shadowing Z^(d)-action non-uniformly partially hyperbolic ergodic measure

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Incidence and risk factors of depression in patients with metabolic syndrome

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World Journal of Psychiatry 2024年第2期14卷 245-254页

作者： Li-Na zhou xian-Cang Ma Wei Wang Department of Psychiatry The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shaanxi ProvinceChina

BACKGROUND Many studies have explored the relationship between depression and metabolic syndrome(MetS),especially in older people.China has entered an aging society.However,there are still few studies on the elderly in Chinese communities.AIM To investigate the incidence and risk factors of depression in MetS patients in China's Mainland and to construct a predictive model.METHODS Data from four waves of the China Health and Retirement Longitudinal Study were selected,and middle-aged and elderly patients with MetS(n=2533)were included based on the first wave.According to the center for epidemiological survey-depression scale(CESD),participants with MetS were divided into depression(n=938)and non-depression groups(n=1595),and factors related to depression were screened out.Subsequently,the 2-,4-,and 7-year follow-up data were analyzed,and a prediction model for depression in MetS patients was constructed.RESULTS The prevalence of depression in middle-aged and elderly patients with MetS was 37.02%.The prevalence of depression at the 2-,4-,and 7-year follow-up was 29.55%,34.53%,and 38.15%,respectively.The prediction model,constructed using baseline CESD and Physical Self-Maintenance Scale scores,average sleep duration,number of chronic diseases,age,and weight had a good predictive effect on the risk of depression in MetS patients at the 2-year follow-up(area under the curve=0.775,95%confidence interval:0.750-0.800,P<0.001),with a sensitivity of 68%and a specificity of 74%.CONCLUSION The prevalence of depression in middle-aged and elderly patients with MetS has increased over time.The early identification of and intervention for depressive symptoms requires greater attention in MetS patients.

关键词： Depression Metabolic syndrome Prevalence Risk factor

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Synthesis of Planar-Chiral[2.2]Paracyclophane-Based Oxazole-Pyrimidine Ligands and Application in Nickel-Catalyzed 1,2-Reduction ofα,β-Unsaturated Ketones

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Chinese Journal of Chemistry 2024年第7期42卷 705-710页

作者： Juan Wang Qing-xian Xie xiang Li Chang-Bin Yu Yong-Gui zhou School of Chemistry Dalian University of Technology2 Linggong RoadDalianLiaoning 116024China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning 116023China

The planar-chiral ligands have been widely applied as a class of unique and significant ligands in asymmetric catalysis.Among them,chiral[2.2]paracycyclophane has emerged as a privileged type of planar-chiral framework and has been utilized as an important toolbox due to their structural stability.Herein,we design and synthesize[2.2]paracyclophane-derived oxazole-pyrimidine ligands(abberviated as PYMCOX).These N,N-ligands with stable properties,rigid structure and large steric hindrance performed successfully in nickel-catalyzed asymmetric 1,2-reduction ofα,β-unsaturated ketones,affording the chiral allylic alcohols with up to 99%yield and 99%ee.Meanwhile,this reduction reaction could be conducted on gram-scale without loss of activity and enantioselectivity,and the chiral ligand could be conveniently recovered with high yield.

关键词： Oxazole-pyrimidine ligands Planar chirality Nickel Hydroboration Asymmetric synthesis

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Analysis of risk factors of suicidal ideation in adolescent patients with depression and construction of prediction model

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World Journal of Psychiatry 2024年第3期14卷 388-397页

作者： Jun-Chao zhou Yan Cao Xu-Yuan Xu Zhen-Ping xian Department of Psychosomatic Medicine The Affiliated Lianyungang Hospital of Xuzhou Medical UniversityThe First People's Hospital of LianyungangLianyungang 222000Jiangsu ProvinceChina

BACKGROUND Major depressive disorder is a common mental illness among adolescents and is the largest disease burden in this age group.Most adolescent patients with depression have suicidal ideation(SI);however,few studies have focused on the factors related to SI,and effective predictive models are lacking.AIM To construct a risk prediction model for SI in adolescent depression and provide a reference assessment tool for prevention.METHODS The data of 150 adolescent patients with depression at the First People's Hospital of Lianyungang from June 2020 to December 2022 were retrospectively analyzed.Based on whether or not they had SI,they were divided into a SI group(n=91)and a non-SI group(n=59).The general data and laboratory indices of the two groups were compared.Logistic regression was used to analyze the factors influencing SI in adolescent patients with depression,a nomogram prediction model was constructed based on the analysis results,and internal evaluation was performed.Receiver operating characteristic and calibration curves were used to evaluate the model’s efficacy,and the clinical application value was evaluated using decision curve analysis(DCA).RESULTS There were differences in trauma history,triggers,serum ferritin levels(SF),highsensitivity C-reactive protein levels(hs-CRP),and high-density lipoprotein(HDLC)levels between the two groups(P<0.05).Logistic regression analysis showed that trauma history,predisposing factors,SF,hs-CRP,and HDL-C were factors influencing SI in adolescent patients with depression.The area under the curve of the nomogram prediction model was 0.831(95%CI:0.763–0.899),sensitivity was 0.912,and specificity was 0.678.The higher net benefit of the DCA and the average absolute error of the calibration curve were 0.043,indicating that the model had a good fit.CONCLUSION The nomogram prediction model based on trauma history,triggers,ferritin,serum hs-CRP,and HDL-C levels can effectively predict the risk of SI in adolescent patients with depression.

关键词： Adolescents Depression Suicidal ideation Risk factors Prediction model Ferritin

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Effects of fulvic acid and humic acid from different sources on Hg methylation in soil and accumulation in rice

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Journal of Environmental Sciences 2022年第9期34卷 93-105页

作者： Shu Ran Tianrong He xian zhou Deliang Yin Key Laboratory of Karst Georesources and Environment(Guizhou University) Ministry of EducationGuiyang 550025China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Guizhou Karst Environmental Ecosystems Observation and Research Station Ministry of EducationGuiyang 550025China

Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury(Hg) in paddy fields are still unclear. Here, fulvic acid(FA) and humic acid(HA) extracted from composted straw(CS), composted cow dung(CCD), peat soil(PM) and lignite coal(LC) were used to understand their effects on the methylation and bioaccumulation of Hg in paddy soil by pot experiments. Amendments of both FA and HA largely increased the abundance of Hg-methylating microbes and low-molecular-weight organic matters(e.g, cysteine) in paddy soil. They were also found to change the aromaticity, molecular size and Chromophoric DOM concentration of DOM, and resulted in heterogeneous effects on migration and transformation of Hg. All the FA-amended treatments increased the mobility and methylation of Hg in soil and its absorption in roots. Nevertheless, FA from different sources have heterogeneous effects on transport of Hg between rice tissues. FA-CCD and FA-PM promoted the translocation of Me Hg from roots to rice grains by 32.95% and 41.12%, while FA-CS and FA-LC significantly inhibited the translocation of inorganic Hg(IHg) by 52.65% and 66.06% and of Me Hg by 46.65% and 36.23%, respectively. In contrast, all HA-amended treatments reduced the mobility of soil Hg, but promoted Hg methylation in soil. Among which, HA-CCD and HA-PM promoted the translocation of Me Hg in rice tissues by 88.95% and 64.10%, while its accumulation in rice grains by 28.43% and 28.69%, respectively. In general, the application of some FA and HA as organic modifiers to reduce Hg bioaccumulation in rice is not feasible.

关键词： Humic acid Fulvic acid Methylmercury Accumulation Rice

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Experimental Study on Mixed-Mode(Ⅰ–Ⅱ)Fracture Toughness of Freshwater Ice

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Acta Mechanica Solida Sinica 2024年第2期37卷 252-264页

作者： Yaozhong Xu Mao zhou xian Yi Wen Hua Jiuzhou Huang Wenyu Zhang Shiming Dong Key Laboratory of Deep Underground Science and Engineering Ministry of EducationCollege of Architecture and EnvironmentSichuan UniversityChengdu610065China Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province Sichuan UniversityChengdu610065China China Aerodynamics Research and Development Center/Low Speed Aerodynamics Research Institute Mianyang621000China College of Mechanical and Electrical Engineering Xichang UniversityXichang615000China

Ⅰn recent years,the issue of aircraft icing has gained widespread recognition.The breaking and detachment of dynamic ice can pose a threat to flight safety.However,the shedding and fracture mechanisms of dynamic ice are unclear and cannot meet the engineering needs of ice-shedding hazard assessment.Therefore,studying the fracture toughness of ice bodies has extremely important practical significance.To address this issue,this article uses a centrally cracked Brazilian disk(CCBD)specimen to measure the pure mode Ⅰ toughness and pure mode Ⅱ fracture toughness of freshwater ice at different loading rates.The mixed-mode(Ⅰ–Ⅱ)fracture characteristics of ice are discussed,and the experimental results are compared and analyzed with the theoretical values of the generalized maximum tangential stress(GMTS)criterion considering the influence of T-stress.The results indicated that as the loading rate increases,the pure mode Ⅰ toughness and pure mode Ⅱ fracture toughness of freshwater ice decrease,and the fracture toughness of freshwater ice is more sensitive to the loading rate.Ⅰn terms of fracture criteria,the theoretical value of the ratio of pure mode Ⅱ fracture toughness to pure mode Ⅰ fracture toughness based on the GMTS criterion is in good agreement with the experimental value,while the theoretical value based on the maximum tangential stress(MTS)criterion deviates significantly from the experimental value,indicating that the GMTS criterion considering the influence of T-stress can better predict the experimental results.

关键词： Freshwater ice Fracture criteria Centrally cracked Brazilian disk(CCBD) Mixed-mode(Ⅰ-Ⅱ) Loading rate

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Recent advances in electrocatalytic generation of indole-derived radical cations and their applications in organic synthesis

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Chinese Chemical Letters 2024年第4期35卷 106-123页

作者： Wei zhou Xi Chen Lin Lu xian-Rong Song Mu-Jia Luo Qiang Xiao Key Laboratory of Organic Chemistry of Jiangxi Province Jiangxi Science&Technology Normal UniversityNanchang 330013China

Indole-derived radical cations, open-shell reactive species, display distinctive dual reactivity due to the carbon-centered radical and more electrophilic carbocation, which frequently appear in a variety of single electron oxidation reactions for synthesizing structurally diverse functionalized indoles and indolines. Electrocatalysis is considered as a synthetically attractive and environmentally friendly alternative for driving the single electron oxidation of indoles. Remarkable achievements in electrocatalytic indolederived radical cation-mediated indole functionalization have been realized so far. This review comprehensively summarizes the recent progresses in the applications of electrocatalytic indole radical cations,including C(sp~2)–H functionalization, dearomative 2,3-difunctionalization, and ring-opening reaction, emphasizing the vital single electron oxidation steps of indoles, the substrates scope and limitations, and the reaction mechanisms.

关键词： Electrocatalysis Indole radical cation C-H functionalizatin Dearomative 2 3-difunctionalization

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Flotation separation of feldspar from quartz using sodium fluosilicate as a selective depressant

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Rare Metals 2024年第3期43卷 1288-1300页

作者： Xin Hu xian-Ping Luo Zi-Shuai Liu Yong-Bing Zhang He-Peng zhou Zhi-Zhao Yang Xue-Kun Tang Faculty of Resource and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou341000China Yichun Lithium New Energy Industry Research Institute Jiangxi University of Science and TechnologyYichun336000China

The physical and chemical properties of feldspar and quartz are highly similar,thus they cannot be easily separated effectively.In this work,the flotation separation of feldspar from quartz using sodium fluosilicate(Na_(2)SiF_(6);SF)as a selective depressant was investigated.Moreover,the influence mechanism of SF on the selective flotation separation of feldspar and quartz was investigated via flotation tests,chemical analysis of flotation solution,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and contact angle analysis.The results of the flotation tests show that feld spar and quartz without SF treatment have good floatability.After SF treatment,feldspar still has good floatability,whereas quartz has significantly reduced floatability.Flotation solution chemical analysis shows that the functional group plays an important role in depressing the quartz is[SiF_(6)]^(2-).FTIR,XPS and contact angle analysis results show that[SiF_(6)]^(2-)is adsorbed only on the surface of quartz.Thus,a thin hydrophilic SiOF layer is generated on the surface,which interferes with the adsorption of the collector on the surface of the quartz.This phenomenon leads to a significant reduction in quartz's floatability.Therefore,SF has a good ability to separate feldspar from quartz by flotation.

关键词： Flotation separation Depressants Sodium fluorosilicate Quartz Feldspar

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