Sorption of Radioactive Iodine on Polymeric Sorbents from Aqueous Solutions and Gas Phase

Sorption of various species of radioactive iodine from aqueous and gas phases on polymeric sorbents Styrosorb and Polysorb-1 was studied. These sorbents do not take up ionic species of radioactive iodine (¹³¹I^- and ¹³¹IO₃ ^-) from aqueous solutions. At the same time, both sorbents take up ¹³¹I₂ from aqueous solutions at 25°C. At V/m = 500 ml g^{- 1}, the distribution factors K _d are 1350 and 590 ml g^{- 1} with Styrosorb and Polysorb-1, respectively. These sorbents efficiently recover ¹³¹I₂ from an air flow at 25°C and flow velocity of 0.33 cm s^{- 1}. The sorption capacity of Styrosorb is approximately four times higher than that of Polysorb-1 and amounts to 97.0 mg of I₂ per gram of sorbent. These data are consistent with the specific surface areas of the sorbents.     

铜锌改性活性炭的制备及对水中余氯的去除效果

用电沉积铜锌的方法制得改性活性炭。对改性活性炭进行了表征,并研究了其去除水中余氯的情况。结果表明,铜锌均匀分布在活性炭中,改性后的活性炭,对水中余氯的去除率远高于原活性炭。     

Sorption of Iodine,Cesium, and Strontium Radionuclides on Alkaline-Earth Hydroxyphosphates from Aqueous Solutions

Sorption of ¹³¹I⁻, ¹³¹IO ₃ ⁻ , ¹³⁷Cs⁺, ⁸⁵Sr²⁺, and F⁻ ions on synthesized alkaline-earth (AE) (calcium, strontium, and barium) hydroxyphosphates was studied. These hydroxyphosphates were prepared by the reactions MCl₂ +Na₃PO₄ + NaOH = M₅(PO₄)₃OH; MCl₂ + NH₄OH + (NH₄)₂HPO₄ = M₅(PO₄)₃OH; and MCl₂ + NaOH + (NH₄)₂HPO₄ = M₅(PO₄)₃OH (M = Ca, Sr, Ba). All the tested AE hydroxyphosphates do not sorb ionic species of radioactive iodine from aqueous solutions. The highest sorption power with respect to fluoride ion is exhibited by calcium hydroxyphosphate. The degree of ¹³⁷Cs and ⁸⁵Sr sorption recovery from aqueous solutions upon their 120-min contact with AE hydroxyphosphates is ∼5–25 and ∼15–80%, respectively.__________Translated from Radiokhimiya, Vol. 47, No. 1, 2005, pp. 80–84.Original Russian Text Copyright © 2005 by Kulyukhin, Krasavina, Mizina, Rumer, Tanashchuk, Konovalova.     

Gaseous Products of the Interaction of CH3I with Ag-Containing Sorbents Based on Silica Gel and Aluminum Oxide

Radiochemistry - The IR spectra of the gas phase formed during the interaction of gaseous CH3I with granular sorbents based on SiO2 and γ-Al2O3 containing various Ag and Ni compounds were...     

Filled Fibrous Sorbents Modified with Transition Metal Ferro- and Ferricyanides for Recovery of Americium and Rare-Earth Metals

Filled fibrous sorbents modified with transition metal ferro- and ferricyanides capable to recover americium(III) and rare-earth metals(III) from nitric acid solutions were prepared. The most complete and rapid recovery is attained on complex-forming and cation-exchange sorbents (as filled fibrous materials) saturated with nickel ions. The sorbents are characterized by good kinetic properties and can be used for recovery of the above metals.     

污泥制备活性炭对 Pb(Ⅱ)和Ni(Ⅱ)的吸附和回收利用

在静态条件下研究了用污泥制备的活性炭吸附剂去除水溶液中Pb(Ⅱ)、Ni(Ⅱ)的效果,考察了溶液pH值、吸附时间、吸附剂用量和Pb(Ⅱ)、Ni(Ⅱ)的初始浓度对去除率的影响.结果表明,污泥制备的活性炭吸附剂对Pb(Ⅱ)、Ni(Ⅱ)具有较强的吸附性能,pH值是影响吸附的主要因素;吸附过程符合Langmuir吸附等温式;在试验条件下,其对Pb(Ⅱ)具有更高的去除能力.还探讨了吸附Pb(Ⅱ)、Ni(Ⅱ)后回收铅和镍的可行性.     

A High-Energy Asymmetric Supercapacitor Based on Tomato-Leaf-Derived Hierarchical Porous Activated Carbon and Electrochemically Deposited Polyaniline Electrodes for Battery-Free Heart-Pulse-Rate Monitoring

A simple and scalable method to fabricate a novel high-energy asymmetric supercapacitor using tomato-leaf-derived hierarchical porous activated carbon (TAC) and electrochemically deposited polyaniline (PANI) for a battery-free heart-pulse-rate monitor is reported. In this study, TAC is prepared by simple pyrolysis, exhibiting nanosheet-type morphology and a high specific surface area of ≈1440 m² g⁻¹, and PANI is electrochemically deposited onto carbon cloth. The TAC- and PANI- based asymmetric supercapacitor demonstrates an electrochemical performance superior to that of symmetric supercapacitors, delivering a high specific capacitance of 248 mF cm⁻² at a current density of 1.0 mA cm⁻². The developed asymmetric supercapacitor shows a high energy density of 270 µWh cm⁻² at a power density of 1400 µW cm⁻², as well as an excellent cyclic stability of ≈95% capacitance retention after 10 000 charging–discharging cycles while maintaining ≈98% Coulombic efficiency. Impressively, the series-connected asymmetric supercapacitors can operate a battery-free heart-pulse-rate monitor extremely efficiently upon solar-panel charging under regular laboratory illumination.     

Peculiarities of the Interaction of Calcium Hydroxyapatite and Carbon Nanotubes Deposited from Aqueous Solutions

Technical Physics Letters - The codeposition of calcium salts, phosphorus, and multiwall carbon nanotubes (CNTs) from aqueous solutions in the Ca(OH)2–H3PO4–H2O–CNT system was...     

Sorption of 131I? and 131IO3? from Aqueous Solutions on Porous Inorganic Sorbents Modified with d-Element Ammoniates at 25°C

Sorption of ¹³¹I⁻ and ¹³¹IO ₃ ⁻ from aqueous solutions on porous inorganic sorbents modified with d elements is studied at 25°C. The sorbents modified with Ag, Zn, Ni, Cu, and Co ammoniates are characterized by low distribution coefficients of ¹³¹I⁻ and ¹³¹IO ₃ ⁻ (K _d <150 ml g⁻¹ at V/m = 1000). Calcination of the sorbents modified with Ag, Cu, and Zn ammoniates at a temperature above 250°C affects the chemical state of the metals in the sorbent matrix, which is accompanied by slight increase in K _d of ¹³¹I⁻ and ¹³¹IO ₃ ⁻ as compared to as-prepared samples. With the γ-Al₂O₃-based sorbents modified with Ni or Cu, K _d of ¹³¹I⁻ and ¹³¹IO ₃ ⁻ is well comparable with that for the Ag-modified sorbents based on MSKG silica gel.__________Translated from Radiokhimiya, Vol. 47, No. 3, 2005, pp. 265–268.Original Russian Text Copyright © 2005 by Kulyukhin, Mizina, Krasavina, Rumer, Konovalova, Tanashchuk, Bogachev.     

胺基改性二氧化硅气凝胶的制备及对刚果红的吸附性能

超轻多孔二氧化硅气凝胶具有极低密度、超高孔隙率和大比表面积的特点,是优异的吸附剂载体.但是,二氧化硅气凝胶骨架表面以硅羟基为主,对污染物的吸附选择性差、吸附容量低.本研究采用共前驱体的方法制备了胺基改性二氧化硅气凝胶块体材料,系统考察了其对模拟污染物阴离子染料刚果红的吸附性能.结果表明,胺基改性二氧化硅气凝胶对刚果红有优异的吸附性能,在较宽pH(3～9)范围内,吸附容量可达800～900 mg/g,吸附等温线符合Langmiur模型;胺基改性气凝胶对刚果红的吸附速率快,1 h内吸附量可达饱和吸附量的80％以上,吸附动力学符合准二级动力学模型;动态吸附实验也显示胺基改性气凝胶对刚果红具有优异的的吸附穿透容量.故改性二氧化硅气凝胶是一种性能优异的阴离子染料吸附剂.     

Extraction of Scandium from Various Media with Triisoamyl Phosphate: 1. Extraction of Sc and Impurity Metals from Aqueous Nitric Acid Solutions

The main features of extraction of Sc from aqueous nitric acid solutions with triisoamyl phosphate (TIAP) were studied. It was shown that Sc passes into the organic phase in the form of Sc(NO₃)₃·3TIAP. The extraction isotherms of Sc from its aqueous HNO₃ solutions and from those containing salting-out agents (LiNO₃, NH₄NO₃) with TIAP in dodecane were obtained. The distribution factor of Sc was studied in relation to the concentrations of TIAP, salting-out agent, and HNO₃. The extraction of Sc and impurity metals (Zr, Th, REE) with TIAP was studied at widely varied HNO₃ concentration in the aqueous phase. The separation factors of Sc from impurity metals were determined.     

以荷叶制备多级孔碳硫复合正极材料及性能研究

以荷叶为原料, 采用多阶炭化的方法, 得到高比表面积(572.1 m²/g)和存在大量多级孔尤其微孔(平均孔径3.31 nm)结构居多的炭骨架, 继而用高能球磨法及熔融法与单质硫进行复合制备出不同含硫量(48wt%, 62wt%, 71wt%)碳/硫复合材料。通过XRD、FESEM、EDS和TG对材料结构和形貌进行表征, 结果表明硫被均匀固定在多孔碳材料的类石墨烯层状结构和类微米棒结构中。充放电测试表明, 62wt%含硫量的复合正极材料性能表现最佳, 在0.1C, 1.2~2.8 V范围内充放电, 首次放电比容量达1246 mAh/g, 100次循环后依旧保持在600 mAh/g, 制备出的复合正极材料对多硫化物的“穿梭效应”起到了抑制作用。     

活化条件对酚醛基活性炭布结构及其电化学性能的影响

以实验室自制的酚醛基纤维布为原料,通过水蒸气活化制备了系列酚醛基活性炭布(ACCs),利用低温N_2(77K)吸附法测定了所制活性炭布的孔结构,将所制备的活性炭布用做超级电容器电极材料,用恒流充放电法和交流阻抗技术考察了所制模拟电容器的电化学性能(电解液:1M(CH_2CH_3)_3CH_3NBF_4/PC).结果表明:随着活化温度的升高或活化时间的延长,所制活性炭布的比表面积和平均孔径增大,中孔比表面积也得到明显提高.活性炭布的比电容随着比表面积的增加而增大,其中950℃活化90min的样品在50mA·g~(-1)电流密度下的比电容达到158F·g~(-1).电容保持率(C_(500)/C_(50))随着样品中孔比表面积的增加而增大,900℃活化120min的样品的电容保持率达到91.1%;随着平均孔径的增大,表征电极导电性的参数IR降减小.     

Use of Layered Double Oxides and Hydroxides of Mg and Al for Removing Dyes from Aqueous Solutions Containing 137Cs, 90Sr, 90Y,and U(VI)

Radiochemistry - The possibility of removing dyes from aqueous solutions containing 137Cs, 90Sr, 90Y, and U(VI) using layered double oxides (LDOs) and hydroxides (LDHs) of Mg and Al was examined....     

Atomically Transition Metals on Self‐Supported Porous Carbon Flake Arrays as Binder‐Free Air Cathode for Wearable Zinc−Air Batteries

Metal single‐atom materials with their high atom utilization efficiency and unique electronic structures usually show remarkable catalytic performances in many crucial chemical reactions. Herein, a facile and easily scalable “impregnation‐carbonization‐acidification” strategy for fabricating a class of single‐atom‐anchored (including cobalt and nickel single atoms) monolith as superior binder‐free electrocatalysts for developing high‐performance wearable Zn–air batteries is reported. The as‐prepared single atoms, supported by N‐doped carbon flake arrays grown on carbon nanofibers assembly (M SA@NCF/CNF), demonstrate the dual characteristics of excellent catalytic activity (reversible oxygen overpotential of 0.75 V) and high stability, owing to the greatly improved active sites' accessibility and optimized single‐sites/pore‐structures correlations. Furthermore, wearable Zn–air battery based on Co SA@NCF/CNF air electrode displays superior stability under deformation, satisfactory energy storage capacity, and good practicality to be utilized as an integrated battery system. Theoretical calculations reveal a mechanism for the promotion of the catalytic performances on single atomic sites by lowering the overall oxygen reduction/evolution reaction barriers comparing to metal cluster co‐existing configuration. These findings provide a facile strategy for constructing free‐standing single‐atom materials as well as the engineering of high‐performance binder‐free catalytic electrodes.     

KOH和ZnCl2活化剂对苎麻秆基活性炭微观结构的影响

以废弃苎麻秆为原料,通过KOH、ZnCl2活化及直接炭化三种方式制备样品。采用扫描电镜(SEM)、N2吸附等温线和X射线衍射(XRD)对碳质材料的微观骨架、孔分布和晶体结构进行分析。结果表明,样品微观形貌呈现多孔性。炭化样中含两种孔径大小的多边形孔道结构,且被一定厚度的孔壁隔开,孔壁上含有较多未通透的孔。基于吸附等温线及BET理论,KOH和ZnCl2样品比表面积分别为1194.22 m2/g和741.9 m2/g。ZnCl2活性炭总孔容为0.38 cm3/g,平均孔径为2.408 nm,与之相比,KOH样品总孔容变为1.5倍,平均孔径达1.911 nm。XRD研究表明,正是活化反应导致材料晶型变化,添加KOH使活性炭石墨微晶形成明显乱层结构,促进了微孔和中孔的形成。     

A New Method for Removing and Binding Th(IV) and Other Radionuclides by In Situ Formation of a Sorbent Based on Fibrous Cerium(IV) Hydrogen Phosphate in Liquid Media

A novel method was suggested for removing Th(IV) and other radionuclides from liquid media. The method consists in formation of the sorbent, fibrous cerium(IV) hydrogen phosphate, directly in the aqueous solution. The sorbent shows the highest performance in the removal of Th(IV). The sorbent can also serve as a host material for the subsequent Th(IV) disposal.     

Influence of Aging on the Physical-Mechanical Properties of Acrylic Resin Films Cast from Aqueous Dispersions and Organic Solutions

The physical-mechanical properties of the enteric copolymers, poly(methacrylic acid, ethyl acrylate) Eudragit® L100-55, and Eudragit® L30D have been investigated. Free films of the copolymer containing varying levels of glyceryl triacetate (triacetin) and citrate ester (Citroflex®) plasticizers were prepared by both aqueous and solvent casting techniques. Conditioned films were stored at different humidities and temperatures for predetermined time periods prior to testing. Free films with plasticizer concentration ranging from 0 to 30% by weight of the polymer demonstrated that physical aging at room temperature resulted in physical-mechanical changes as the stress-strain curves indicated a decrease in the percent elongation with increases in the tensile strength. Films prepared from the aqueous latex approached a constant state of equilibrium at a faster rate than films prepared from isopropyl alcohol, where the mechanical properties approach a relatively constant value. Free films containing varying amounts of the plasticizer, triethyl citrate, were stored under different humidity and temperature conditions. In addition, a headspace-gas chromatography (HSGC) method was developed to correlate solvent residues with mechanical properties. The results indicated that an increase in temperature and humidity accelerated the rate of solvent evaporation as a function of time. High vacuum and low humidity conditions were demonstrated to be ineffective conditions for solvent removal. Solvent residues were found in all films after 48 hours of exposure to temperatures up to 60°C and/or exposure to relatively high humidity conditions. A direct relationship between plasticizer content and rate of solvent evaporation from the film was established. Higher concentrations of the plasticizer were found to augment the evaporation of the solvents. This enhanced evaporation was due to the stronger molecular interaction forces between the polymer and the plasticizer than between the polymer and the solvent.     

In Situ Two‐Step Activation Strategy Boosting Hierarchical Porous Carbon Cathode for an Aqueous Zn‐Based Hybrid Energy Storage Device with High Capacity and Ultra‐Long Cycling Life

Aqueous Zn‐based hybrid energy storage devices (HESDs) exhibit great potential for large‐scale energy storage applications for the merits of environmental friendliness, low redox potential, and high theoretical capacity of Zn anode. However, they are still subjected to low specific capacities since adsorption‐type cathodes (i.e., activated carbon, hard carbon) have limited capability to accommodate active ions. Herein, a hierarchical porous activated carbon cathode (HPAC) is prepared via an in situ two‐step activation strategy, different from the typical one‐step/postmortem activation of fully carbonized precursors. The strategy endows the HPAC with a high specific surface area and a large mesoporous volume, and thus provides abundant active sites and fast kinetics for accommodating active ions. Consequently, pairing the HPAC with Zn anode yields an aqueous Zn‐based HESD, which delivers a high specific capacity of 231 mAh g^?1 at 0.5 A g^?1 and excellent rate performance with a retained capacity of 119 mAh g^?1 at 20 A g^?1, the best result among previously reported lithium‐free HESDs based on carbon cathodes. Further, the aqueous Zn‐based HESD shows ultra‐long cycling stability with a capacity retention of ≈70% after 18 000 cycles at 10 A g^?1, indicating great potential for environmentally friendly, low‐cost, and high‐safety energy storage applications.