螯合树脂塔智能化控制的优化

介绍了螯合树脂塔的工作流程,分析了原控制系统存在的问题,提出了智能化改造方案,达到了预期效果。     

Biocomposite based electrode for effective removal of Cr (VI) heavy metal via capacitive deionization

Abstract

This study focuses on the fabrication of biocomposite electrode and removal of Cr (VI) ions from wastewater using a capacitive deionization (CDI) method. The activated carbon (AC) was synthesized from Bael fruit shell (BS). The synthesized AC surface has a macroporous and mesoporous structure with the large specific surface area (617.72?m² g^?1) and high adsorption capacity. The cyclic voltammetry and CDI were performed for the detection and for the removal of chromium (VI) ions, respectively. The lower level of detection of Cr (VI) by a modified electrode was found to be 10 ppt. SEM, BET, and FTIR analyses were performed to explore the surface properties of electrode materials. The removal efficiency was achieved 100% by using biocomposite electrode with an applied potential of 15?V. The highest percent removal mechanism consists of electrosorption and electroreduction due to the affinity between polyvinyl alcohol modified electrode and Cr (VI) ions, under electrochemically faradic process.     

Polymer hydrogel cross-linked by inorganic nanoparticles for removing trace metal ions

Hydrogels for absorbing metal ions in wastewater have attracted more attentions in the environmental field especially for recent years. The removal efficiency of hydrogel adsorbents for eliminating metal ions is highly related with the effective contact between adsorbents and adsorbates. However, poor water absorption capacity of the hydrogel adsorbents would restrict on the expose of adsorption sites to the targeted subjects, causing undesirable removal ratio (RR) especially for metal ions at trace level. Thereby, the reported hydrogel adsorbents mainly focus on the removal of high content but not the trace level of metal ions so far. In this work, poly(acrylamide) (PAM)/poly(acrylic acid) (PAA)/Ca(OH)₂ composite hydrogel is applied to adsorb trace metal ions. Swelling ratio of such PAM/PAA/Ca(OH)₂ gel reaches 2,530 g/g, resulting in effective exposure of active sites and further expected RR for trace metal ions. The RRs of such adsorbent for Cu²⁺ (initial concentration C₀ = 0.064 mg/L), Al³⁺ (C₀ = 0.27 mg/L), Co²⁺ (C₀ = 0.59 mg/L), Cr⁶⁺ (C₀ = 0.52 mg/L), Mn²⁺ (C₀ = 0.55 mg/L), Ni²⁺ (C₀ = 0.59 mg/L), Zn²⁺ (C₀ = 0.65 mg/L), Ag⁺ (C₀ = 1.08 mg/L), and La³⁺ (C₀ = 1.39 mg/L) are 56.6, 80.8, 41.3, 29.3, 34.6, 44.6, 55.9, 45.8, and 35.5%, respectively. This work broadens the application of hydrogel adsorbent for eliminating trace metal ions from polluted water.     

Impact of gypsum on flotation of scheelite and fluorite using sodium oleate as collector

ABSTRACT

In this study, effect of calcium and gypsum on scheelite and fluorite was investigated using sodium oleate as collector. Micro-flotation and contact angle results showed that the adsorption of calcium could inhibit the hydrophobicity of scheelite and fluorite. Moreover, sulfate could enhance the inhibition. FT-IR results showed that calcium could be priori precipitated into calcium oleate and adsorb on mineral surface. The adsorption of calcium could increase the scheelite potential to IEP, while it showed limited effect on fluorite potential. However, the interaction of calcium on scheelite and fluorite in gypsum solution was more complex than that in calcium solution.     

Superior lithium storage performance of hierarchical N-doped carbon encapsulated NaTi2(PO4)3 microflower

Na-superionic conductor (NASICON) structured NaTi₂(PO₄)₃ (NTP) as anode shows broad prospect in aqueous lithium ion battery. However, inherent low electrical conductivity of NaTi₂(PO₄)₃ remains a pivotal issue to be resolved. Herein, we report N-doped carbon encapsulated NaTi₂(PO₄)₃ microflower (NTP-CN) as anode for aqueous lithium ion battery, which is prepared via solvothermal way. NTP-CN with unique structural feature displays superb electrochemical performances. It delivers the discharge capacities of 131.2, 110.1, and 84.3 mAh g⁻¹ at 0.2, 3.0, and 15 C, respectively, 38.8, 33.8, and 51.1 mAh g⁻¹ higher than these of pristine NTP. NTP-CN also shows remarkable cycling stability at 6 C after 1000 cycles (capacity retention: 88.8%), superior to NTP (70.7%). The outstanding properties of NTP-CN may be due to that microflower structure can increase touching area between electrolyte and electrode, and carbon coating for electrode improves stability in aqueous electrolyte and ameliorates electrical conductivity. Moreover, nitrogen doping can further enhance hydrophilicity and conductivity of the sample, and also form lots of defects on electrode surface, which is beneficial for the intercalation/deintercalation of Li ions. This work reveals that the combination of microflower structure and N-doped carbon layer offers a promising method to improve electrochemical performances of NaTi₂(PO₄)₃.     

FeO0.7F1.3/C Nanocomposite as a High‐Capacity Cathode Material for Sodium‐Ion Batteries

Searching high capacity cathode materials is one of the most important fields of the research and development of sodium‐ion batteries (SIBs). Here, we report a FeO_0.7F_1.3/C nanocomposite synthesized via a solution process as a new cathode material for SIBs. This material exhibits a high initial discharge capacity of 496 mAh g^?1 in a sodium cell at 50 °C. From the 3^rd to 50^th cycle, the capacity fading is only 0.14% per cycle (from 388 mAh g^?1 at 3^rd the cycle to 360 mAh g^?1 at the 50^th cycle), demonstrating superior cyclability. A high energy density of 650 Wh kg^?1 is obtained at the material level. The reaction mechanism studies of FeO_0.7F_1.3/C with sodium show a hybridized mechanism of both intercalation and conversion reaction.     

Metal complexation studies of amylopectin‐graft‐poly[(N,N‐dimethylacrylamide)‐co‐(acrylic acid)]: a biodegradable synthetic graft copolymer

Synthesis of amylopectin‐graft‐poly[(N,N‐dimethylacrylamide)‐co‐(acrylic acid)] was carried out using solution polymerization technique with potassium persulfate as the initiator. The graft copolymer was characterized by measuring molecular weight using size exclusion chromatography, thermal analysis and Fourier transform infrared (FTIR) spectroscopy. The synthetic graft copolymer was used for the removal of some potentially toxic metal ions, Cu(II), Zn(II) and Ni(II), from their aqueous solutions. Various operating parameters like the amount of adsorbent, solution pH, contact time and temperature were studied. The adsorption data were well described by the pseudo‐second‐order and Langmuir isotherm models. Metal complexation studies were carried out experimentally using cyclic voltammetry and UV‐visible and FTIR spectroscopies. The metal complex structure was also studied theoretically using density functional theory with the Gaussian 09 program and the geometry of the complex structure was optimized. The metal complexation ability of the graft polymer was in the order Cu(II) > Ni(II) > Zn(II). Calculation of the various thermodynamic parameters was also done. The negative value of free energy change indicates the spontaneous nature of the adsorption. © 2015 Society of Chemical Industry     

直接熔样正热电离质谱法测定二硼化锆中硼同位素丰度

本工作选择m/z88(23 Na210BO2+)和m/z89(23 Na211BO2+)的Na2BO2+作为检测离子,研究了同位素干扰、涂样技术、ZrB2样品处理等对硼同位素测定的影响,建立了快速准确测定ZrB2中硼同位素丰度的正热电离质谱法。实验复现了硼同位素标准物质的标准值,对酸溶法分解试样后涂样和直接熔融法涂样测量结果的精密度进行了比较。结果表明,采用直接熔融法涂样可以快速准确地测定ZrB2中硼同位素丰度,δ10B同位素丰度测定结果精密度优于0.020%。     

Electrical properties of calcia-stabilised zirconia ceramics

The electrical properties of cubic, calcia-stabilised zirconia ceramics, Ca_xZr_1-xO_2-x: 0.12 ≤ x ≤ 0.18 have been investigated using impedance spectroscopy to separate bulk, grain boundary and electrode contact impedances. The most appropriate equivalent circuit to characterise the bulk response required inclusion of a dielectric component, represented by a series RC element, in parallel with the oxide ion conductivity represented by a parallel combination of a resistance, capacitance and constant phase element. The dielectric component may be attributed to defect complexes involving immobile oxygen vacancy pairs whereas long range conduction involves single oxygen vacancies.     

Al-doping induced superior lithium ion storage capability of LiNiO2 spheres

To optimize the performance of LiNiO₂ with minimal modification of the pristine structure, a facile solid-state approach, based on the interdiffusion of elements at the solid/solid interface, is developed to achieve uniformly Al-doped LiNiO₂ using alumina coated Ni(OH)₂ spheres as the precursor. The resulting LiNi_0.95Al_0.05O₂ material exhibits excellent discharge capacity (209.9 mAh g⁻¹ at 0.1 C) and cycling stability with a capacity retention of 85.10% after 200 cycles at 0.5 C. This is ascribed to the improved reversibility of the phase transitions by Al-doping as revealed by in-situ XRD characterization. The Al-doping also endows the material with superior rate capability due to the enlarged interlayer spacing in the structure and alleviation of the side reactions at the electrode/electrolyte interface, favorable for lithium ion diffusion. An optimal amount of doped Al is necessary for ensuring the structure stability and interface ionic conductivity of the LiNiO₂ spheres. Thus, the present strategy may provide an opportunity to optimize the performance of LiNiO₂, with uniform doping of a small amount of Al, producing a promising cathode material for advanced lithium ion batteries.