Bacterial kinetics and environmental capacity in he Western Xiamen Harbour

A principle, which has usually been applied to biochemical treatment for waste water is presently introduced into the study on marine microbiological ecology and employed in the estimation of environmental capacity. By means of a selection of 3 models for the microbial growth or for its oxygen consumption and determinations of concerned parameters in the field and the laboratory, the environmental capacity for the Western Xiamen Harbour is evaluated to be 37 t·d-1 of BOD5 in gross or 28 t·d-1 in net (with some 25% of the gross capacity consumed by a present ecosystem) if BOD5 is controlled without excess of 3 mg·din-3 in the sea water; it means that an amount of domestic waste water equal to 28 t of BOD5 can be naturally self-purified in this sea area everyday. Furthermore it is found that the K value, a constant of oxygen-consumed kinetics, shows possitive correlation to the concentration of BOD5 in the same system and total bacterial number (TB) in the seawater also to BOD5 with a regression equation TB (108 dm-3)=9. 91×BOD5 (mg·dm-3) + 1. 74 (n=32, r=0. 544 1, P<0. 01).

Fast hydrogenation kinetics of acridine as a candidate of liquid organic hydrogen carrier family with high capacity

Hydrogen has been deemed as one of the most efficient energy carriers for a broad variety of industrial applications[1,2].Large-scale,low-cost hydrogen production,safe storage and delivery represent a tremendous technological challenge and have become a subject of intense research and development activities in the past few decades[3–5].

Atomic Ni directional-substitution on ZnIn_(2)S_(4) nanosheet to achieve the equilibrium of elevated redox capacity and efficient carrier-kinetics performance in photocatalysis

It is a challenge to coordinate carrier-kinetics performance and the redox capacity of photogenerated charges synchronously at the atomic level for boosting photocatalytic activity.Herein,the atomic Ni was introduced into the lattice of hexagonal ZnIn_(2)S_(4) nanosheets(Ni/ZnIn_(2)S_(4))via directionalsubstituting Zn atom with the facile hydrothermal method.The electronic structure calculations indicate that the introduction of Ni atom effectively extracts more electrons and acts as active site for subsequent reduction reaction.Besides the optimized light absorption range,the elevation of Efand ECBendows Ni/ZnIn_(2)S_(4) photocatalyst with the increased electron concentration and the enhanced reduction ability for surface reaction.Moreover,ultrafast transient absorption spectroscopy,as well as a series of electrochemical tests,demonstrates that Ni/ZnIn_(2)S_(4) possesses 2.15 times longer lifetime of the excited charge carriers and an order of magnitude increase for carrier mobility and separation efficiency compared with pristine ZnIn_(2)S_(4).These efficient kinetics performances of charge carriers and enhanced redox capacity synergistically boost photocatalytic activity,in which a 3-times higher conversion efficiency of nitrobenzene reduction was achieved upon Ni/ZnIn_(2)S_(4).Our study not only provides in-depth insights into the effect of atomic directional-substitution on the kinetic behavior of photogenerated charges,but also opens an avenue to the synchronous optimization of redox capacity and carrier-kinetics performance for efficient solar energy conversion.

MOF-derived porous graphitic carbon with optimized plateau capacity and rate capability for high performance lithium-ion capacitors

The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl solu-tion.The as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion storage.Additionally,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).

Effects of different pulsed vacuum drying strategies on drying kinetics,phenolic composition,and antioxidant capacity of chrysanthemum(Imperial chrysanthemum)

This work aimed to discuss effects of pulsed vacuum drying(PVD)at different temperatures(45°C,50°C,55°C and 60°C),vacuum durations(5 min,10 min and 15 min)and multi-stage heating on drying kinetics,colour attributes,phenolic compounds and antioxidant capacity of chrysanthemum(Imperial chrysanthemum).Results indicated that successive temperature increase reduced the drying time and enhanced the drying rate and moisture diffusivity.Lower temperature(45°C)and the multi-stage(35°C-55°C-60°C)drying presented the superiority in the protection of color,preservation of phytochemical composition(chlorogenic acid,luteolin,total phenolic and total flavonoid content)and improvement of antioxidant capacity(DPPH and FRAP)of chrysanthemum,which was attributed to the low-oxygen drying environment and reduction of thermal degradation losses.Based on the results of drying efficiency and drying quality,the multi-stage heating(35°C-55°C-60°C)has the excellent potential to produce high-quality dried chrysanthemum on a commercial scale.

Universal organic anodes enable safe low-cost aqueous rechargeable batteries with long cycle life,high capacity, and fast kinetics

Future battery advances and economies of scale will help scrub CO2emissions from transportation and the grid.Economical energy storage lets battery-powered electric vehicles replace internal combustion engines in the transportation sector,which now accounts for the plurality of CO2emissions.For grid-scale applications,the benefits of adding storage are many and well documented[1–2].Beyond increased penetration of intermittent renewable energy generated from such as solar panels

Scaffold-regulation buffered MoS_(2)anode kinetics for high-performance Na-/K-ion storage

Designing a highly conductive scaffold with unique function has great significance in elevating the stor-age properties of molybdenum sulfide(MoS_(2))for sodium-and potassium-ion batteries.Herein,we show that forming a three-dimensional(3D)highly conductive dual backbone that consists of titanium nitride nanowires(TiN)coated on 3D carbon fiber(CF)could suppress the poor conductivity of MoS_(2).Theo-retical calculations predict that both TiN and CF boost the electronic conductivity,while the MoS_(2)will promote high ionic adsorption owing to the suitable adsorption energy.The as-prepared CF@TiN/MoS_(2),with mass loading up to 12.5 mg cm^(−2),achieves a high areal capacity of up to 5.40 mAh cm^(−2)under the current density of 0.6 mA cm^(−2)for sodium storage.The excellent performance of the hybrid can be attributed to buffer and conductivity enhancer features,allowing Na-ion to directly have contact with the CF@TiN/MoS_(2)hybrid.A series of electrochemical analyses including cyclic voltammetry and symmetric cell analyses affirm the significant improvement in transport kinetics.More importantly,the CF@TiN/MoS_(2)also achieves a high areal capacity of 3.29 mAh cm^(−2)under the current density of 0.3 mA cm^(−2)as anode material for potassium ion batteries(PIBs),demonstrating that the scaffold-regulated strategy is a feasible strategy to enhance the kinetics of MoS_(2)-based anodes for secondary-ion batteries and beyond.

The Cation Exchange Capacity of Fibrous Feedstuff and Its Nutritive Characteristics

Current researches on the nutritive characteristics of fibrous feedstuff through determining the feedstuff cation exchange capacity (CEC) to evaluate its nutritive value at home and abroad were comprehensively discribed. and the methods of determining CEC value and the correlation between CEC value and chemical compositions, pH value, and the effect of CEC value on the digestion kinetics in ruminants were also emphatically introduced. The results of research showed that the CEC values of different feedstuff are different, closely correlated with nitrogen and acid detergent fibre (ADF) and lignin (LIG) content of the feedstuff. At the same time, there are markedly effect of CEC value in diet on the nutrients flow of digesta in the digestive tract of ruminants, the degradation rate and digestibility of nutrients in the rumen.

Calculation of Environmental Capacity of Petroleum Hydrocarbon in Jiaozhou Bay

The method has been established to calculate the environmental capacity (ECO), surplus environment capacity (SECO) of water with respect to marine petroleum hydrocarbons associated with oil (PHAOs) and the self-purification capacity (SPCO) of main self-purification process to PHAOs in the Jiaozhou Bay, China, according to the dynamic model for distribution of marine PHAOs among multiphase environments. The variation of concentration of PHAOs in the Jiaozhou Bay is well simulated by the dynamic model. Based on the model, the ECo, SECo of water with respect to PHAOs in the Jiaozhou Bay were calculated during the last 10 years under the first-class and second-class quality standard requirement, according to SPCO of main self-purification process to PHAOs. The results show that about 200 tons of PHAOs could be discharged into the Jiaozhou Bay for maintaining the first class seawater quality standard, and about 600 tons of PHAOs for the second class seawater quality standard later.

Cadmium sorption from aqueous solutions onto Iranian sepiolite:Kinetics and isotherms

This work aims to investigate the efficiency of Fariman sepiolite from Iran as an adsorbent to remove Cd from aqueous solutions. The effects of different experimental factors such as the initial Cd concentration, contact time and the sorbent dose were investigated through a series of batch adsorption experiments. The results show that the adsorption capacity of sepiolite for Cd increases with the contact time, the initial concentration of Cd solutions and the sorbent dose. Sorption of Cd by Fariman sepiolite is rapid within the first hour of the experiment and then slowly increases until a pseudo equilibrium is approached at 8 h. The results also show that the time-dependent Cd sorption data are better described with pseudo second-order （7〉0.999） than that of pseudo first-order （r2〉0.971） kinetic model. Equilibrium isotherm studies show that the experimental data are better correlated by the Freundlich adsorption isotherm （7〉0.995） than the Langmuir （P〉0.825）. It is suggested that both adsorption and cation exchange reactions are responsible for the sorption of Cd by the sepiolite, and the mineral has a very good potential to remove Cd from aqueous solutions.

铝胁迫下5种内生真菌的生长与吸收动力学特征

为了解铝(Al)胁迫下不同内生真菌的生长情况及其对Al^(3+)的吸收动力学特征,筛选抗铝性较强的优良菌株。选取分离自南方酸性红壤区耐铝树种千年桐的5种不同内生真菌(分别隶属于拟盘多毛孢属、链格孢属、盾壳霉属、青霉属和嗜热真菌属)为供试材料,设置5个Al^(3+)浓度(0、0.555、0.746、1.111、1.852 mmol·L^(-1)),研究内生真菌的生长情况及其对Al^(3+)的吸收、吸附特征,并分析5种内生真菌的阳离子交换量和吸收动力学情况。结果表明:5种内生真菌菌株的生物量总体随着Al^(3+)浓度的升高呈现先增加后减少的趋势;当Al^(3+)浓度低于1.111 mmol·L^(-1)时,5种内生真菌均具有较强的耐铝性,当Al^(3+)浓度为1.852 mmol·L^(-1)时,5种菌株对Al^(3+)的耐受能力显著下降(P<0.05);各菌株对Al^(3+)的吸收和吸附均随着Al^(3+)浓度的升高而增加。其中,青霉属菌株的平均生长量达158 mg,其生物量显著大于其他4种菌株(P<0.05),其耐受指数、吸收动力学指标及吸附性Al^(3+)含量也相对较高,而其吸收性Al^(3+)含量均小于其他4种菌株。综合上述各项指标,相较于其他4种菌株,青霉属菌株细胞壁的吸附性Al^(3+)含量较多,能够防御Al^(3+)进入细胞内。

磷石膏淋滤液磷在红黏土中的迁移转化与吸附特性研究

为了探究磷石膏淋滤液磷在土壤中的迁移转化及赋存状态,文章以贵州某磷石膏堆场为研究区,通过室内物理模拟实验与土壤吸附实验,分析磷石膏淋滤液磷在红黏土中的迁移转化特征,并探讨了红黏土对磷的吸附成因。研究结果表明:不同磷石膏厚度与红黏土厚度,对磷石膏淋滤液磷的迁移有显著影响,其中磷石膏厚度越大,淋滤液中磷浓度越大,而红黏土土层厚度越大,淋滤液中磷浓度越低;磷石膏淋滤液磷在红黏土中的迁移转化过程中,其各形态之间不断发生转变,并有一部分会被红黏土所吸附,从而使磷浓度随之降低,主要存在形态为可溶磷与无机磷,占比分别为80%~94%和80%~95%,有机磷与颗粒态磷含量较小,占比分别为5%~20%和5%~16%;红黏土对磷石膏淋滤液中磷的最大吸附量为0.23mg/g,且红黏土对磷的吸附等温曲线符合Freundlich方程,相关系数R2为0.98678,吸附过程符合准二级动力学模型,相关系数R2为0.96414。

Study on the hydrogen absorption properties of a YGdTbDyHo rare-earth high-entropy alloy

This study investigated the microstructure and hydrogen absorption properties of a rare-earth high-entropy alloy(HEA),YGdTbDyHo.Results indicated that the YGdTbDyHo alloy had a microstructure of equiaxed grains,with the alloy elements distributed homogeneously.Upon hydrogen absorption,the phase structure of the HEA changed from a solid solution with an hexagonal-close-packed(HCP)structure to a high-entropy hydride with an faced-centered-cubic(FCC)structure without any secondary phase precipitated.The alloy demonstrated a maximum hydrogen storage capacity of 2.33 H/M(hydrogen atom/metal atom)at 723 K,with an enthalpy change(ΔH)of-141.09 kJ·mol^(-1)and an entropy change(ΔS)of-119.14 J·mol^(-1)·K^(-1).The kinetic mechanism of hydrogen absorption was hydride nucleation and growth,with an apparent activation energy(E_(a))of 20.90 kJ·mol^(-1).Without any activation,the YGdTbDyHo alloy could absorb hydrogen quickly(180 s at 923 K)with nearly no incubation period observed.The reason for the obtained value of 2.33 H/M was that the hydrogen atoms occupied both tetrahedral and octahedral interstices.These results demonstrate the potential application of HEAs as a high-capacity hydrogen storage material with a large H/M ratio,which can be used in the deuterium storage field.

CuO/BiOCl异质结催化剂的合成及其光催化性能研究

以微球状氯氧化铋(BiOCl)为模板,合成了CuO/BiOCl异质结催化剂,利用扫描电子显微镜、X射线衍射仪、荧光分光光度计等对催化剂形貌和结构进行了表征;以亚甲基蓝(MB)为降解目标,探究了CuO与BiOCl物质的量比、MB染料初始质量浓度、催化剂质量、溶液pH等对CuO/BiOCl催化性能的影响,并研究了该催化剂的循环再生能力及光催化反应机理。结果表明:在可见光照射下,当CuO与BiOCl物质的量比为1∶15,催化剂质量为0.050g,MB初始质量浓度为25mg/L时,光催化效率最高,吸附过程符合一级动力学模型,且该催化剂具有良好的循环再生能力。在催化过程中空穴h+起主要作用,羟基自由基和超氧自由基均起次要作用。

贡柑皮热风干燥动力学及抗氧化活性变化研究

目的探究贡柑副产物果皮的热风干燥过程(50、60、70、80℃)中水分的干燥动力学变化规律及对应干燥温度下的抗氧化活性变化。方法借助Fick定律和Arrhenius方程对贡柑皮干燥过程水分的扩散情况、干燥活化能进行研究,解析了干燥过程贡柑皮的抗氧化活性变化。结果随着干燥的进行,贡柑皮的水分逐渐减少,且干燥温度越高,所需的干燥时间越短。贡柑皮水分干燥动力学规律遵循Page模型。水分扩散系数随温度的升高而增大,贡柑皮干燥所需的活化能为18.0374 kJ/mol。贡柑皮的1,1-二苯基-2-三硝基苯肼(2,2-diphenyl-1-picrylhydrazyl,DPPH)自由基抑制率随干燥温度升高而逐步降低,最优值在50℃,为49.73%;2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸[2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonate),ABTS]阳离子自由基、超氧化物歧化酶(superoxide dismutase,SOD)抑制率以及总抗氧化能力(total antioxidant capacity,T-AOC)随干燥温度的升高先上升后降低,均在60℃时最优,分别为51.95%、61.99%和5.13 mmol/g,但贡柑皮在4个热风干燥温度下羟自由基清除率并无显著性差异。结论在恒定的风速下,综合效能、干燥时间和抗氧化能力,确定60℃为最佳的热风干燥温度,为“岭南佳果”贡柑的高效利用和产业链持续发展提供了理论支持。

MIL-53(Fe)在土壤Sb(Ⅲ)污染修复中的应用研究

采用溶剂热法制备了金属有机框架材料MIL-53(Fe),并将其应用于吸附土壤中的锑(Sb)。以MIL-53(Fe)为吸附剂,吸附水溶液中Sb(Ⅲ),探讨了溶液温度、pH值、吸附剂用量、Sb(Ⅲ)初始浓度、腐殖酸含量对吸附性能的影响,分析了吸附等温线和吸附动力学。结果表明,吸附剂用量3%,修复15 d后的土壤毒性浸出试验可浸出的Sb(Ⅲ)浓度降低了94.2%。溶液pH值和腐殖酸含量对吸附性能基本没有影响。对于25 mL浓度10μg/mL的Sb(Ⅲ)溶液,加入20 mg MIL-53(Fe)即可达到良好的吸附效果。Sb(Ⅲ)初始浓度对MIL-53(Fe)吸附Sb(Ⅲ)的影响较大,吸附平衡条件下吸附剂最大吸附容量为102.9 mg/g。该吸附过程的吸附等温线与Freundlich模型拟合相匹配,吸附动力学符合伪二级动力学模型。

An Adsorption Kinetic Model for Sulfur Dioxide Adsorption by ZL50 Activated Carbon

A semi-empirical adsorption kinetic model was proposed with the time compensation method to describe the chemisorption of SO2 in flue gas by carbon adsorbents for flue gas purification.The change in adsorption capacity and adsorption rate with time at different water vapor concentrations and different SO2 concentrations was studied.The model was in good agreement with experimental data.The surface reaction was probably the rate controlling step in the early stage for SO2 adsorption by ZL50 activated carbon.The parameters m and n in the nth order adsorption kinetic model were related to the magnitude of the time compensation and adsorption driving force,respectively.The change of parameter n with water vapor concentrations and sulfur dioxide concentrations was studied and some physical implications were given.The sum of square errors was less than 1.0 and the average absolute percentage deviations ranged from 0.5 to 3.2.The kinetic model was compared with other models in the literature.

A comprehensive review of the effect of different kinetic promoters on methane hydrate formation

Gas hydrates have recently emerged as a better alternative for the production,storage,and transportation of natural gases.However,factors like slow formation rate and limited storage capacity obstruct the possible industrial application of this technique.Different types of promoters and synergists have been developed that can improve the kinetics and storage capacity of gas hydrates.This review focuses on different kinetic promoters and synergists that can be utilized to enhance the storage capacity of hydrates.The main characteristics,structure and the possible limitations of the use of these promoters are likewise portrayed in detail.The relationship between structure and storage capacity of hydrates have also been discussed in the review.Current status of production of gas from hydrates,their restrictions,and future difficulties have additionally been addressed in the ensuing areas of the review.

O—正丁基—N—异丁基硫氨酯在黄铜矿表面的吸附热力学和动力学

O—正丁基—N—异丁基硫氨酯(NBIB)是一种新型铜硫分离捕收剂.利用紫外-可见分光光度计进行吸附量测定,研究吸附温度、pH值、时间和捕收剂浓度等对NBIB在黄铜矿表面吸附量的影响,并进行吸附热力学和动力学研究.纯矿物浮选实验表明,NBIB对黄铜矿具有较强的捕收能力,且受pH影响很小.在温度分别为288、298、308 K,p H值为6、9、12条件下,NBIB在黄铜矿表面的吸附量随NBIB浓度的增加而增大,当平衡浓度达到0.5×10^(-4)mol·L^(-1),吸附量增加幅度变小.相同pH值时,吸附量随温度的升高而增加,推测NBIB捕收剂在黄铜矿表面的吸附为吸热过程.p H值对吸附量影响不大.将吸附量数据进行Langmuir和Freundlich方程线性拟合,NBIB在黄铜矿表面的吸附过程更符合Langmuir单分子层吸附模型.热力学计算结果表明,吸附的吉布斯自由能变(?G)均为负值,焓变(?H)和熵变(?S)均为正值,说明黄铜矿吸附NBIB的过程可能为自发进行的、熵驱动的、吸热的化学吸附.吸附温度从288 K到308 K,吸附量随吸附时间和温度的增加而增大,当吸附时间达到20 min之后,吸附量的增加趋势变缓.动力学计算表明,二级反应速率方程的线性拟合结果更好,利用二级反应速率方程计算所得的平衡吸附量更接近于实验平衡吸附量,推测NBIB在黄铜矿表面的吸附符合二级吸附动力学模型.

Apparent activation energy of mineral in open pit mine based upon the evolution of active functional groups

This study aimed to investigate the mechanism of mineral spontaneous combustion in an open pit. On the study of coal and mineral mixture in open pit mines, as well as through the specifc surface area and Search Engine Marketing (SEM) experiments, the specifc surface area and aperture characteristics of distribution of open pit coal sample and pit mineral mixture samples were analyzed. Thermal analysis experiments were used to divide the oxidation process was divided into three stages, and the thermal behavior characteristics of experimental samples were characterized. On the basis of the stage division, we explored the transfer law of the key active functional groups of the experimental samples. The apparent activation energy calculation of the key active groups, performed by combining the Achar diferential method with the Coats–Redfern integral method, microstructural and oxidation kinetic properties were revealed. The resulted showed that the mixed sample had high ash, the fxed carbon content was reduced, the specifc surface area was far lower than the raw coal, the large aperture distribution was slightly higher than the medium hole, the micropore was exceptionally low, the gas adsorption capacity was weaker than the raw coal, the pit coal sample had the exceedingly more active functional groups, easy to react with oxygen, more likely to occur naturally, and its harm was relatively large. The mixed sample contained the highest C–O–C functional group absorbance. The functional groups were mainly infuenced by the self-OH content, alkyl side chain, and fatty hydrocarbon in the sample. The main functional groups of the four-like mixture had the highest apparent activation energy, and the two reactions were higher in the low-temperature oxidation phase.