Plasma-assisted aerogel interface engineering enables uniform Zn^(2+)flux and fast desolvation kinetics toward zinc metal batteries

The poor reversibility of Zn anodes induced by dendrite growth,surface passivation,and corrosion,severely hinders the practical applicability of Zn metal batteries.To address these issues,a plasmaassisted aerogel(PAG)interface engineering was proposed as efficient ion transport modulator that can simultaneously regulate uniform Zn^(2+)flux and desolvation behavior during battery operation.The PAG with ordered mesopores acted as an ion sieve to homogenize Zn deposition and accelerate Zn^(2+)flux,which is favorable for corrosion resistance and dendrite suppression.Importantly,the plasma-assisted aerogel with abundant hydrophilic groups can facilitate the desolvation kinetics of Zn^(2+)due to the multiple hydrogen-bonding interaction with the activated water molecules,thus accelerating the Zn^(2+)migration kinetics.Consequently,the Zn/Zn cell assembled with PAG-modified separator demonstrates stable plating and stripping behavior(over 1400 h at 1 mA cm^(-2))and high Coulombic efficiency(99.8%at1 mA cm^(-2)after 1100 cycles),and the Zn‖MnO_(2)full cell shows excellent long-term cycling stability and maintains a high capacity of 154.9 mA h g^(-1)after 1000 cycles at 1 A g^(-1).This study provides a feasible approach for the large-scale fabrication of aerogel functionalized separators to realize ultra-stable Zn metal batteries.

Heavy metal removal from aqueous solution using carbonaceous K_2S-impregnated adsorbent

A novel carbonaceous adsorbent for heavy metal removal was prepared from raw coal by one-step simple sulfur impregnation using K2S. Raw coal was mixed with K2S powder and then heated at 800℃ for 30 min in nitrogen to produce K2S char. The sulfur content and form in K2S char were determined, and the ability of K2S char to adsorb Zn^2＋, Cd^2＋ and Pb^2＋ was examined. The K2S impregnation was effective at impregnating sulfur into coal, especially in the form of elemental, thiophenic and sulfatic sulfur. The sulfur content of K2S char was higher than those of raw coal and pyrolysis char. The Zn^2＋ removal in 2.4 mmol/L of Zn^2＋ solution by K2S char was higher than raw coal with the removal rate of 100%. K2S char adsorbed Pb^2＋ and Cd^2＋ in 24 mmol/L of Pb^2＋ and Cd^2＋ solution with the removal rate of 97% and 35%, respectively. The elution extents of adsorbed Pb^2＋ and Cd^2＋ were zero in distilled water and 27% in 0.1 mol/L HCl solution. These results indicated that an effective adsorbent for heavy metal ions was prepared from coal using K2S sulfur impregnation, and that the adsorbed metals were strongly retained in K2S char.

Facile fabrication of spherical flower-like Mg(OH)2 and its fast and efficient removal for heavy metal ions

Spherical flower-like Mg(OH)_(2) was fabricated from MgSO_(4) effluent and its adsorption performance for heavy metal ions was evaluated.The appropriate fabrication conditions are as follows:Mg^(2+)/NH4OH molar ratio of 1:0.5,temperature of 120°C and time of 1 h at Mg^(2+)concentration of 2 mol/L.Spherical flower-like Mg(OH)_(2) composed of ultra-thin sheets exhibits an excellent adsorption ability for Ni^(2+),Cu^(2+),Zn^(2+),Pb^(2+),Fe^(3+)and Co^(2+),and the adsorption reaches the equilibrium in 6 min.The maximum adsorption capacities of the studied heavy metal ions onto Mg(OH)_(2) at 20°C are 58.55,85.84,44.94,485.44,625.00 and 27.86 mg/g,respectively.The adsorption is well fitted by the Langmuir model,indicating that the adsorption is monolayer.The adsorption kinetics follows the pseudo-second-order model.Chemisorption is the operative mechanism.Spherical flower-like Mg(OH)_(2) is a qualified candidate for heavy metal ions removal.

Extraction of Heavy Metals from Solid Material by Supercritical CO_2

Extraction of heavy metal ions from solid matrix by means of an incorporation of chelating agents with supercritical carbon dioxide（scCO2） was investigated experimentally. Four commercially available chelating agents, diethylammonium diethyldithiocarbamate（Et2NH2DDC）, trifluoroacetylacetone（TFA）, hexafluoroacetylacetone（HFA） and thenoyltrifluoroacetone（TTA） were tested. The extraction experiments were conducted at 50 °C and 1.39×107― 2.80×107 Pa. According to the experimental results, for the extraction of Cu2＋, all the chelating agents investigated here are effective. For other metal ions, such as Pb2＋, Ni2＋ and Cd2＋, Et2NH2DDC exhibited a better extraction result, while other chelating agents were less effective. This investigation is expected to provide a tentative evaluation on the scCO2-based metal extraction from solid media.

TiO2 nanoparticles in aquatic environments:impact on heavy metals distribution in sediments and overlying water

The extensive application of TiO_(2)nanoparticles(NPs)highlights the importance of investigating their influence on aquatic systems.In this work,the effect of TiO_(2)NPs on heavy metals speciation was studied on a lab scale.For this goal,a series of aquaria containing water,sediment,and TiO_(2)NPs with various concentrations were set up.The study results revealed that TiO_(2)NPs caused(copper)Cu,(mercury)Hg,(titanium)Ti,and(zinc)Zn to be adsorbed by sediments in the forms of exchangeable and Fe-Mn species.According to measurements,30μg/L of TiO_(2)NPs made Cu,Hg,Ti and Zn concentration in the water column decreased from 33,1.14,20,and 32 to 4,0.58,3,and 22.3μg/L,respectively.Manganese(Mn)was also adsorbed by sediment,and in all experiments,its concentration in the water column reduced from 44 to about 20μg/L.Due to the photocatalytic capacity of TiO_(2)NPs,arsenic(As)concentration in the water column increased from 0 to 8.7μg/L with the introduction of30μg/L of TiO_(2)NPs.The sequential extraction results showed that in all experiments,concentrations of lead(Pb),nickel(Ni),and cobalt(Co)remained constant in different chemical species of sediment,which meant conservative behavior of them in presence of TiO_(2)NPs.In addition,a remarkable change was observed in water quality parameters such as ORP,TDS,TOC,BOD,NO3’and PO_(4)after the introduction of TiO_(2)NPs to aquaria.The reason behind these changes could be related to the decomposition of sediment organic content by TiO_(2)NPs.

Influences of Organic Acids and Heavy Metals on Cr（VI） Photoreduction Catalyzed by TiO2 Suspension

Photocatalytic reduction of Cr（VI） by TiO2 suspension has been studied with the purpose of removing the toxic and carcinogenic Cr（VI） ions from water. The photocatalytic reduction was carried out in batch reactor, in which the influences of the presence ofmalonic and oxalic acids as well as of iron and lead ions on the degree of the reduction have been systematically evaluated. The results of the research indicated that the presence of malonic and oxalic acids with increasing concentration can improve the photoreduction. The increase in the Cr（V1） photoreduction is due to OH radical capturing by the organic acids so that it prevents the recombination of the OH radical and the free electron, and therefore can provide enough electron supply for Cr（VI） photoreduction. The effectiveness of Cr（VI） photoreduction is also enhanced by the addition of increasing concentration of both Fe（Ⅲ） and Pb（Ⅱ） ions through synergic effect. It is also found that the degree of the photopreduction is strongly influenced by solution acidity and the most effective Cr（VI） photoreduction is obtained at lower pH than 5, either in the absence or presence of the organic acids and the heavy metal ions.

Comments on“Adsorption behavior of heavy metal ions by carbon nanotubes grown on microsized Al_2O_3 particles”

Recently, Hsieh and Horng [1] published the paper entitled as above. In section 3 results and discussion, the authors mentioned the first and the second order kinetic models without any quotations. In fact these two kinetic models have been published [2-5]. In order to distinguish a kinetics model based on the ad- sorption capacity of a solid from the one based on the concentration of a solution, Lagergren＇s first-order rate equation has been called pseudo-first-order [6-7]. The Lagergren＇s equation has been widely cited, but there are far more mistakes made in the quotation and in the reference section of papers, including the title, the author＇s name, journal title, year of publishing, volume, and page number [3]. In addition, the second order kinetic expression for the adsorption systems of divalent metal ions using sphagnum moss peat has been reported by Ho [8].

改性膨润土对废水中Cu^(2+)、Zn^(2+)去除效果的研究

在对钙基膨润土原土进行钠化的基础上,用阴离子表面活性剂十二烷基硫酸钠(SDS)与阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)改性制得了有机改性膨润土。通过对含Cu2+、Zn2+废水处理试验,发现Na-膨润土及有机改性膨润土对Cu2+、Zn2+的吸附符合Langmuir方程,有机改性膨润土比Na-膨润土具有更大的吸附容量。试验对影响Cu2+、Zn2+去除的吸附时间、pH、膨润土用量、温度等因素进行了优化研究。当改性膨润土用量为5.0 g.L-1时,对实际电镀废水中Cu2+、Zn2+去除率分别为97.8%和87.6%。

斜纹夜蛾幼虫不同组织对Zn^2＋积累作用的比较研究

通过在人工饲料中添加不同质量分数的Zn2,研究了植食性昆虫斜纹夜蛾Spodoptera lituraFabricius连续3代幼虫取食含不同质量分数Zn2+饲料后,第1和第3代6龄幼虫不同组织对Zn2+的积累作用。结果表明,经连续3个世代的胁迫,Zn2+在第1、3代斜纹夜蛾6龄幼虫脂肪体、表皮和中肠中的积累量随幼虫饲料中Zn2+质量分数及胁迫时间的增加而升高;中肠对Zn2+的积累作用最强,表皮次之,脂肪体最低。

膨润土对重金属离子Pb^(2+),Zn^(2+),Cr(VI),Cd^(2+)的吸附性能

试验研究了pH值、吸附时间和吸附剂用量对膨润土吸附重金属离子Pb2+,Zn2+,Cr(VI)和Cd2+的影响.结果表明,在本试验的pH值、吸附时间及吸附剂用量条件下,膨润土对Pb2+,Zn2+,Cd2+的吸附效果均优于其对Cr(VI)的吸附效果;pH值是影响上述吸附的重要因素,离子交换和表面络合是上述吸附的主要形式.

重金属Zn^2＋胁迫下麦长管蚜的取食行为

为了探索重金属锌长期胁迫对麦长管蚜(Sitobion avenae)取食行为的变化影响,在模拟自然的实验室条件下,用不同浓度Zn^(2+)溶液浇灌土壤,通过土壤-小麦-蚜虫体系连续处理麦长管蚜15代,用EPG(刺探电位技术)对第1、5、10、15代成蚜的取食行为进行了监测。结果表明,第1代和第5代时,200 mg/kg的Zn^(2+)处理后np波和C波的总持续时间和数量显著低于对照,800mg/kg的Zn^(2+)使其显著增加。到第15代,高剂量的Zn^(2+)处理后np波和C波的总持续时间和数量均显著高于对照。涉及分泌唾液的E1波持续时间及涉及被动取食营养的E2波出现次数并未受到低剂量Zn^(2+)的显著影响,但高剂量的Zn^(2+)处理后单独E1波、伴随稳定E2的E1波总持续时间及E2波的数量均显著降低。麦长管蚜的取食行为会受到重金属锌的影响并且会在高剂量Zn^(2+)的胁迫条件下产生积累效应,而低剂量的Zn^(2+)则促进麦长管蚜对小麦的取食行为。针对重金属而言,此效应发生改变的关键浓度为400 mg/kg,蚜虫取食行为发生改变的关键世代为第5代和第10代。

重金属Zn^(2+)·Cd^(2+)对田菁生理生化指标的影响

[目的]研究重金属Zn2+、Cd2+对田菁生理生化指标的影响。[方法]以田菁幼苗为试验材料,在水培条件下,研究了Zn2+、Cd2+对田菁幼苗生理上的毒害。[结果]Zn2+、Cd2+对田菁幼苗毒害作用显著。随着Zn2+、Cd2+胁迫浓度的增高,田菁叶片叶绿素含量表现为先增高而后降低的趋势;可溶性蛋白含量表现为下降趋势;脯氨酸含量表现为上升趋势;SOD与POD活性表现为先升高而后降低的趋势。Zn2+、Cd2+对田菁幼苗的毒害作用强度不同,Cd2+表现出更强的毒害作用。[结论]该研究为了解海滨地区的重金属污染状况,治理生态环境提供了参考依据。

Ti_(3)C_(2)T_(x)超薄纳米片高效率去除废水中重金属的研究

通过刻蚀剥离法制备了Ti_(3)C_(2)T_(x)超薄纳米片,探究了其对废水中重金属离子的吸附特性。通过SEM、XRD、AFM、FT-IR、Raman对Ti_(3)C_(2)T_(x)超薄纳米片的形貌和结构进行了表征,通过ICP-MS对处理前后水体中重金属离子的含量进行了测试。结果表明剥离的Ti_(3)C_(2)T_(x)超薄纳米片表面含有结构缺陷和羟基,当水体中Cu(Ⅱ)、Pb(Ⅱ)、Cr(Ⅵ)初始浓度为50 mg/L时,47.5 mg Ti_(3)C_(2)T_(x)超薄纳米片对其的去除效率高达90%以上,尤其是对Pb(Ⅱ)的去除效率达到了98.81%,吸附性能远高于大孔树脂、硅藻土和活性炭等常见吸附试剂。在Na(Ⅰ)、Cu(Ⅱ)、Pb(Ⅱ)、Cr(Ⅵ)4种离子共存溶液中,Ti_(3)C_(2)T_(x)超薄纳米片对于Pb(Ⅱ)和Cr(Ⅵ)的去除依然可以达到92%以上。通过动力学和吸附等温拟合,Ti_(3)C_(2)T_(x)纳米片对Pb(Ⅱ)的吸附符合拟二级动力学模型和Langmuir等温模型,对Pb(Ⅱ)的最大吸附量和最低检出限分别为81.7 mg/g和0.0094 mg/L。Ti_(3)C_(2)T_(x)超薄纳米片对重金属离子的吸附特性在化学工业、食品加工的废水处理中具有良好的应用前景。

Comparative adsorption of heavy metal ions in wastewater on monolayer molybdenum disulfide

To maximize the potential of monolayer molybdenum disulfide(MoS2)sheet in the disposal of heavy metal ions in wastewater,we compared the adsorption of several common heavy metal ions(including Cr^(3+),Ni^(2+),Cu^(2+),Zn^(2+),Cd^(2+),Hg^(2+),and Pb^(2+))in wastewater on the monolayer MoS2 sheet through first-principles calculation.Our simulation results show that the monolayer MoS2 sheet is a potential heavy metal adsorption material because of the attractive interaction between them.The most negative adsorption energy determines that the TMo site is the most stable adsorption site for the heavy metal ions.The attractive interaction is considered as chemical adsorption,and it is closely related to charge transfer.The orbital hybridization between S p and heavy metal ions p and d states electrons contributes to the adsorption,except the orbital hybridization between S p and Pb p states electrons contributes to the Pb^(2+) adsorption.All the results show that the monolayer MoS2 sheet is most suitable for removing Ni^(2+) and Cr^(3+) ions from wastewater,followed by Cu^(2+) and Pb^(2+).For the ions Cd^(2+),Zn^(2+),and Hg^(2+),its adsorption strength remains to be improved.

Modeling the Spatial Distribution of Soil Heavy Metals Using Random Forest Model—A Case Study of Nairobi and Thirirka Rivers’ Confluence

Modeling the spatial distribution of soil heavy metals is important in determining the safety of contaminated soils for agricultural use. This study utilized 60 topsoil samples (0 - 30 cm), multispectral images (Sentinel-2), spectral indices, and ancillary data to model the spatial distribution of heavy metals in the soils along the Nairobi River. The model was generated using the Random Forest package in R. Using R2 to assess the prediction accuracy, the Random Forest model generated satisfactory results for all the elements. It also ranked the variables in order of their importance in the overall prediction. Spectral indices were the most important variables within the rankings. From the predicted topsoil maps, there were high concentrations of Cadmium on the easterly end of the river. Cadmium is an impurity in detergents, and this section is in close proximity to the Nairobi water sewerage plant, which could be a direct source of Cadmium. Some farms had Zinc levels which were above the World Health Organization recommended limit. The Random Forest model performed satisfactorily. However, the predictions can be improved further if the spatial resolutions of the various variables are increased and through the addition of more predictor variables.

重金属离子Zn^(2+)和Cu^(2+)胁迫对白三叶种子萌发及幼苗生长的影响

采用不同浓度的Zn^(2+)、Cu^(2+)溶液处理白三叶种子,研究Zn^(2+)、Cu^(2+)对白三叶种子萌发及幼苗生长的影响,旨在为白三叶在Zn^(2+)、Cu^(2+)污染土壤中的种植适宜性提供参考。结果表明,当Zn^(2+)浓度达到125 mg/L、Cu^(2+)浓度为60 mg/L及以上时,白三叶种子的发芽率、发芽势均受到显著抑制,对发芽指数无明显影响,但却显著影响种子的活力指数,并显著抑制了幼苗胚根、胚芽以及生物量的增加,且浓度越高抑制作用越明显,对胚根的抑制作用明显强于胚芽;白三叶种子萌发和幼苗生长对Zn^(2+)的耐受力大于Cu^(2+),不适宜在Zn^(2+)浓度达125 mg/L及以上的土壤中种植,而Cu^(2+)污染的限制浓度为60 mg/L、且250 mg/L可认为是白三叶幼苗的致死剂量。

Na_(2)S改性生物炭高效吸附重金属离子:制备及吸附机理

以废弃芦苇为原料、硫化钠(Na_(2)S)为改性剂,制备了对Pb^(2+)、Cd^(2+)、Zn^(2+)具有高效吸附性能的Na_(2)S改性生物炭(BCS)。通过扫描电镜-能谱(SEM-EDS)、红外光谱(FTIR)、元素分析等手段对改性前后的生物炭进行了表征。结果显示,Na_(2)S改性能够为生物炭引入多种含硫官能团,提升孔体积并增加比表面积。Langmuir模型拟合结果表明,随着改性剂Na_(2)S溶液浓度的增加,BCS对重金属离子的吸附能力得到提升。在pH为2.0~6.0的范围内,BCS对重金属离子的吸附能力随pH增加逐步增强。在pH=6.0时,BCS对Pb^(2+)、Cd^(2+)、Zn^(2+)的最大吸附量分别为494.99、131.14、94.89 mg/g。根据动力学实验结果可知,BCS对重金属离子的吸附行为符合伪二级动力学模型。吸附机理主要包括表面官能团的络合、离子交换和静电吸附。本研究可为废弃物的再利用以及废水中的重金属的高效去除提供一种环境友好且可行的解决方案。

膨润土对煤矸石溶出重金属Zn^(2+)的吸附研究

采用淋溶吸附试验,考察煤矸石淋溶液pH值、膨润土用量、吸附时间、重金属浓度4个指标,研究膨润土对煤矸石淋溶液中重金属Zn^(2+)的吸附效果。结果表明,吸附过程在96 h后达到平衡状态;最佳膨润土掺量为30%,该掺量下吸附达到平衡时Zn^(2+)吸附率均大于72%;吸附平衡状态下,膨润土对煤矸石淋溶液中Zn^(2+)吸附量随pH值增加而减小;吸附过程符合双常数模型。

膨润土-白泥复合吸附剂处理含Zn^(2+)酸性废水实验研究

为高效处理含重金属Zn^(2+)的酸性矿山废水(AMD),将具有碱性的造纸白泥和具有黏结性和吸附性的膨润土复合,并掺加造孔剂,通过高温焙烧制备新型复合颗粒吸附剂,建立Zn^(2+)的吸附等温式和动力学方程.研究结果表明:复合吸附剂最大碱度释放量为82.9 mg/g(以Ca_(2)CO_(3)计),投加复合吸附剂可使水样的pH值上升.Freundlich等温模型能更好地描述复合吸附剂对Zn^(2+)的吸附,吸附过程更符合准二级动力学方程.

MoS_(2)及其改性膜去除水中重金属及核素研究进展

近年来,由于工业、核电及其相关产业的快速发展,水中重金属及核素污染不能忽视,水体安全保障成为全球关注的重要问题。二硫化钼(MoS_(2))纳米材料在杀菌、储氢和水净化等领域备受关注,膜技术由于操作简单、效率高等优点成为去除水中重金属及核素的选择之一。本文综述了近5年来MoS_(2)基纳米材料及膜材料在去除水中重金属及核素的研究进展,重点介绍了MoS_(2)合成与改性的主要方法、MoS_(2)去除重金属及核素过程中的主要影响因素及作用机理、MoS_(2)改性膜制备及膜技术去除水中重金属及核素的前沿研究等,旨在高效去除重金属和核素。