Application of Response Surface Methodology for Optimization of Fluoride Removal Mechanism by Newely Developed Biomaterial

The adsorption capacities of new biomaterials derived from lemon leaf (Citrus sp.) toward fluoride ions have been explored by varying different physicochemical parameters such as pH, initial concentration, adsorbent dose, contact time, stirring rate and temperature. The entire study was done through batch process. Maximum fluoride adsorption of 96.9% - 98.8% was achieved with an initial concentration of 10 mg/L. Langmuir isotherm model well expressed fluoride ad- sorption onto LLD-1, LLD-2 and LLD-3. According to correlation coefficient, the fluoride adsorption onto these 3 ad- sorbents was correlated well with pseudo-second-order kinetic model. From thermodynamic study, the spontaneous nature and feasibility of the adsorption process with negative enthalpy (&#916H0) value also supported the exothermic nature were shown. The rate of fluoride adsorption was mathematically described as a function of experimental parameters and was modeled through Box-Behnken (Response surface methodology). The results showed that the responses of fluoride adsorption were significantly affected by the quadratic term of pH, initial concentration, contact time and temperature and the statistical analysis was performed by ANOVA which indicated good correlation of experimental parameters.

粉煤灰提铝残渣制备4A分子筛及Cu(Ⅱ)吸附研究

4A分子筛由于其优异的阳离子交换能力,成为处理重金属废水优良的吸附材料。为了达到以废治废的目的,以粉煤灰酸法提铝残渣为原料制备地质聚合物,再经水热原位转化合成体型化4A分子筛。采用XRD、FT-IR、SEM、BET、TGA等手段对4A沸石进行表征,探讨吸附时间、Cu(Ⅱ)初始浓度、吸附剂用量及溶液p H对其吸附性能的影响,并结合动力学方程和吸附等温线模型对其吸附过程进行研究。结果表明,所合成的4A分子筛孔隙发达且微孔含量较多,总比表面积为71.85 m^(2)/g,其中微孔比表面积为53.91 m^(2)/g,微孔孔径主要集中在1.3 nm左右。体型化4A分子筛吸附Cu(Ⅱ)的最佳条件为吸附时间为240 min、Cu(Ⅱ)初始质量浓度为100 mg/L、吸附剂用量为2.0 g/L、溶液p H为6~9,此时吸附量为32.97 mg/g,Cu(Ⅱ)的去除率可达65.93%。吸附过程符合准二级动力学模型,以化学吸附为主。Langmuir模型拟合效果较好,表明Cu(Ⅱ)在合成4A沸石上的吸附过程为单分子层吸附,且拟合得到的Cu(Ⅱ)的最大吸附量为37.05 mg/g。

基于动态噪声自适应无迹卡尔曼滤波的锂离子电池SOC估计

锂离子电池具有无记忆效应、轻量化、环保等特点,因此常作为电动交通工具、电子设备的能源来源,并适用于各种规模的能源存储。在锂离子电池管理系统中,电池的荷电状态(state of charge,SOC)是最关键的指标之一,其准确估计对于实现电池系统的高效能量管理和优化控制至关重要。因此本文提出了一种基于动态噪声自适应无迹卡尔曼滤波的SOC估计方法。首先,通过间歇放电实验获取电池不同SOC下的开路电压,并进一步拟合得到电池的OCV-SOC曲线,接着采用二阶RC等效电路模型对锂离子电池建模,然后通过混合功率脉冲特性工况测试对电池模型参数进行辨识。由于实际应用中锂离子电池为非线性系统且SOC估计精度容易受到噪声的影响,本文在卡尔曼滤波算法的基础上采用无迹变换处理,加入噪声自适应过程,以实现噪声特性自适应估计,动态调整测量噪声与过程噪声,提高算法鲁棒性以及估计精度。最后选取DST与FUDS工况进行验证,结果表明在不同工况下动态噪声自适应无迹卡尔曼滤波算法的估计平均绝对误差、最大绝对误差以及均方根误差相较于自适应无迹卡尔曼滤波、无迹卡尔曼滤波算法均有降低,其平均绝对误差小于0.59%。本文提出的动态噪声自适应无迹卡尔曼滤波算法能够更准确地估计锂离子电池SOC。

基于二阶随机动力学的多虚拟电厂自趋优能量管理策略

分布式资源(distributed energy resources,DERs)的随机元素会引起多虚拟电厂(multi-virtual power plant,MVPP)系统内虚拟电厂(virtual power plant,VPP)策略频繁变化。对于某主体,如何感知其他主体策略突然变化时对自身收益的影响趋势,并快速调整自身策略,是亟需解决的难点。该文提出基于二阶随机动力学的多虚拟电厂自趋优能量管理策略,旨在提升VPP应对其他主体策略变化时的自治能力。首先,针对DERs异质运行特性,聚焦可调空间构建VPP聚合运行模型;然后,基于随机图描绘VPP策略变化的随机特性;其次,用二阶随机动力学方程(stochastic dynamic equation,SDE)探索VPP收益结构的自发演化信息,修正其他主体策略变化时自身综合收益;再次,将修正收益作为融合软动作-评价(integrated soft actor–critic,ISAC)强化学习算法的奖励搭建多智能体求解框架。最后,设计多算法对比实验,验证了该文策略的自趋优性能。

Removal of Dye Using Lignin-Based Biochar/Poly(ester amide urethane)Nanocomposites from Contaminated Wastewater

The pursuit of incorporating eco-friendly reinforcing agents in polymer composites has accentuated the exploration of various natural biomass-derived materials.The burgeoning environmental crisis spurred by the discharge of synthetic dyes into wastewater has catalyzed the search for effective and sustainable treatment technologies.Among the various sorbent materials explored,biochar,being renewable,has gained prominence due to its excellent adsorption properties and environmental sustainability.It has also emerged as a focal point for its potential to replace other conventional reinforcing agents,viz.,fumed silica,aluminum oxide,treated clays,etc.This study introduces a novel class of polymer nanocomposites comprising of lignin-based biochar particles and poly(ester amide urethane)matrix via a feasible method.The structural evaluation of these nanocomposites was accomplished using Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy,and powder X-ray diffraction.The polymer nanocomposites exhibited superior mechanical properties with an increment in tensile strength factor by 45%in comparison to its pristine matrix,along with an excellent toughness value of 90.22 MJm^(−3)at a low loading amount of only 1 wt%.The composites showed excellent improvement in thermal properties with a sharp rise in the glass transition temperature(Tg)value from−28.15℃to 84℃,while also championing sustainability through inherent biodegradability attributes.Beyond their structural prowess,these polymer nanocomposites demonstrated excellent potential as adsorbents,displaying efficient removal of malachite green and tartrazine dyes from aqueous systems with a removal efficiency of 87.25%and 73.98%,respectively.The kinetics study revealed the pseudo second order model to be the precision tool to assess the dye removal study.Complementing this,the Langmuir adsorption isotherm provided a framework to assess the sorption features of the polymer nanocomposites.Overall,these renewable biochar integrated polymer matrices boast remarkable recovery capabilities up to seven cycles of usage with an excellent dye recovery percentage of 95.21%for the last cycle,thereby defining sustainability as well as economic feasibility.

Recyclable adsorbent of BiFeO_3/Carbon for purifying industrial dye wastewater via photocatalytic reproducible

It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic recyclable adsorbent of BiFeO3/Carbon nanocomposites for purifying simulative industrial dye wastewater. It is found that the structure of the prepared BiFeO3/Carbon nanocomposite is related to the natural structure of the biscuit, annealing temperatures and immersing times, demonstrated by XRD, TEM, UV-Vis and adsorptive activities. Kinetics data shows that the adsorption rate of the adsorbent to the dye is rapid and fitted well with the pseudo-second-order model, that more than 80% of dyes can be removed in the beginning 30 min. The adsorption isotherm can be perfectly described by the Langmuir model as well. It can be seen from the adsorption data that the adsorption performance can reach over 90% at pH ? 2–12, which can imply its universal utilization. The prepared BiFeO_3/Carbon nanocomposites have also displayed excellent capacities(over 90% within 30 min) for adsorption of seven different dyes and their mixed one. According to the five times photocatalytic reproducible experiments, it is proved that BiFeO_3/Carbon nanocomposites show the excellent stability and reproduction for purifying simulative industrial dyes, even the sample have been placed for one year. These research results indicate that the adsorbent BiFeO_3/Carbon can be a suitable material used in treating industrial dye wastewater potentially.

Kinetics and Thermodynamic Studies: Adsorption of Pb, Cr and Ni Ions from Spent Lubrication Oil (SLO) Using Acid Modified Clay

Adsorption of Pb, Cr, and Ni ions from spent lubrication oil (SLO) by sulphuric acid modified clay (SAMC) was investigated considering the effect of contact time and temperature of the adsorption system. The removal percentage of the heavy metals was found to be temperature and contact time-dependent. Adsorption of the heavy metals increases with an increase in temperature and contact time with 95.0% - 100% adsorption recorded at the temperature of 331 K with the equilibration time of 12 hours. The thermodynamic and kinetics investigation of the adsorption process showed that the adsorption of these metals by the modified adsorbent is a spontaneous and endothermic physical adsorption process that followed the pseudo-second-order kinetic model.

Characterization of Cassava Root Husk Powder: Equilibrium, Kinetic and Modeling Studies as Bioadsorbent for Copper(II) and Lead(II)

This study was aimed to investigate Pb(II) and Cu(II) ions removal ability from aqueous solution by cassava root husks (CRH) as a cheap, sustainable and eco-friendly bioadsorbent. The CRH was characterized by Fourier Transform Infrared (FTIR) spectroscopy which indicated the availability of various functional groups for metal coordination and the result was supported by elemental analysis studies. UV-Visible spectral studies indicated the presence of oxalate () and it could possibly interact with metal ions to give rise to a stable chelated coordination complex which affects metal ions removal efficiency. Bioadsorption process was carried out as a function of metal concentration, contact time, pH of the solution, particle size, and dosage of the adsorbent. Experimental results indicated the optimal adsorption condition of pH 4 for both Pb(II) and Cu(II) ions, dosage of 0.1 g/0.1L and 1 g/0.1L for Pb(II) and Cu(II) ions respectively, adsorption equilibrium time of 2 and 25 minutes for Pb(II) and Cu(II) respectively, and concentration of 0.5 mg/L for both metal ions. Kinetic data best fitted pseudo-second-order model and not the pseudo-first-order model. Equilibrium data best fitted the Freundlich model than the Langmuir model. Specific surface area and pore volume studies indicated that CRH is non-porous and hence rapid adsorption kinetics is expected. Supporting the experimental results, molecular modeling studies performed using Schrödinger software predicted several sites in the structure capable of docking with metal ions.

Interpretation of Adsorption Thermodynamics and Kinetics

A complete study of adsorption processes will be less complete if the structure and dynamics of its different elements and how they interact is not well captured. Therefore, the extensive study of adsorption thermodynamics in conjunction with adsorption kinetics is inevitable. Measurable thermodynamic properties such as temperature equilibrium constant and their non-measurable counterparts such as Gibbs free energy change, enthalpy, entropy etc. are very important design variables usually deployed for the evaluation and prediction of the mechanism of adsorption processes.

线性化模型下二阶逆变器的混沌控制

针对线性化模型下二阶逆变器发生的非线性分岔与混沌行为,加入控制手段增加稳定域与抗扰性。首先构建了二阶逆变器的系数线性化迭代模型,运用分岔图、折叠图再现了其产生的混沌行为,并寻求系统的Jacobian矩阵和平衡点。然后加入延时反馈控制,并基于朱里判据给出了控制参数的限定条件。最后为说明所加入混沌控制方法的优越性,开展了数值仿真模拟实验。结果表明,延时反馈控制使系统比例参数K的分岔值从0.573后移至0.973,且当直流源输入侧电压突变时,系统仍保持在稳定运行状态。表明施加延时反馈控制后,二阶逆变器运行的稳定域增加且整体的抗扰性增强。

考虑电池储能老化和需求侧响应的交直流混合配电网动态重构方法

现有的电池储能模型一方面认为电池的充放电功率和效率为固定不变的,另一方面有关电池储能的充放电过程对循环老化的影响缺少考虑,这与电池单元本体的非线性等效电路模型相违背。因此,考虑电池储能的循环老化成本、需求侧响应,提出了交直流混合配电网动态重构方法。通过对实际电池储能的充放电功率的运行区域进行采样,在凸包络的采样点集合中将非理想状态下的电池储能模型重构为线性模型。在此基础上,分别建立了基于累积吞吐电量和放电深度的循环老化成本模型,构建了综合成本最小化的交直流混合配电网动态重构模型。并采用混合整数二阶锥规划方法求解。在改进的33节点算例上仿真验证了所提基于放电深度的循环老化成本模型的经济性,分析了交直流混合配电网重构方法经济性的影响因素。

一种储能电池的数据解析及模型验证方法

随着新型能源系统构建,大量储能电池接入系统,运用物联网、大数据等技术提升其管理水平势在必行。基于储能电池运行特性分析,提出了一种数据解析及模型验证方法。分析了储能电池的数据采集及传输方式,研究了控制器局域网络(CAN)报文的帧解析及数据提取方法,给出了具体算法流程。结合电池二阶等效电路模型,研究了储能电池数据模拟方案,包括开路电压查表获取方法及动态电压迭代算法。研究了个人计算机(PC)侧工具开发方案,包括界面设计及功能布局。实例应用结果表明,该方法可用于储能电池数据解析及模型验证。

天祝褐煤腐植酸对Ni^(2+)离子吸附性能研究

通过FTIR、FR分析了天祝腐植酸吸附重金属Ni2+离子前后的红外光谱、荧光强度的变化,对重金属离子Ni2+进行了吸附性能及机理研究。结果表明:在室温条件下(20℃～25℃),吸附最佳pH=6,吸附平衡时间约为5h。符合Freundlich吸附模型,相关系数R=0.9998,特性常数n为2.49。腐植酸对Ni2+有较好的吸附性能,其吸附过程可用Ho准二级反应动力学模型描述。

改性玉米秸秆对水中磷酸根的吸附动力学研究

将化学改性后的玉米秸秆制备阴离子交换剂,重点研究了改性玉米秸秆对磷酸根的吸附动力学特性.通过静态实验,考察了在不同pH、温度、磷酸根初始浓度条件下,改性玉米秸秆对磷酸根吸附效果的影响,并分别用伪一级动力学方程、伪二级动力学方程、修正伪一级动力学方程和颗粒内扩散方程进行拟合,计算出相应的速率常数.结果表明,Langmuir等温模式能更好地描述改性玉米秸秆对磷酸根的吸附效果,并且随着温度的升高,改性玉米秸秆对磷酸根的最大吸附量逐渐减小.改性玉米秸秆对磷酸根的吸附是一个快速吸附过程,30 min内即可达到吸附平衡,该吸附过程符合伪二级动力学方程和颗粒内扩散方程,吸附速率主要受颗粒内扩散控制.随着初始浓度的增大,伪二级吸附速率常数逐渐减小,颗粒内扩散速率常数逐渐增大.通过改性玉米秸秆对磷酸根的吸附动力学研究,可以为反应器的设计和污水处理装置的运行提供基础信息,对于去除水溶液中磷酸根的技术应用具有重要实际意义.

沉水植物龙须眼子菜(Potamogeton pectinatus)对镉、铅的吸附特性

采用龙须眼子菜(Potamogeton pectinatus)干样为实验材料,研究了龙须眼子菜对溶液中镉、铅吸附的基本特征。相同浓度不同时间条件下的吸附实验结果显示,龙须眼子菜对溶液中镉、铅离子的吸附速度很快,大约20min就能达到平衡,吸附的限速过程是小孔扩散过程,随着时间的延长,吸附的动力学特征可用假二次方程描述。相同时间不同浓度条件下的吸附实验结果显示,龙须眼子菜对镉、铅的最大吸附量分别能达到32368和24776mg·kg-1,吸附的浓度动力学特征符合Langmuir曲线方程。所有结果都表明,龙须眼子菜能有效地从溶液中去除镉和铅,可以用于水体镉、铅污染的植物修复,也可把龙须眼子菜干样作为一种新的吸附剂用于去除工业废水中的镉和铅。

改性沸石对猪场沼液氮磷吸附特性与机理分析

针对猪场沼液氮磷含量高、有机污染严重、难以处理的问题,采用经氯化钠溶液改性沸石为载体对沼液中氮磷吸附特性和去除机理进行分析研究,考察了沸石投加量、吸附时间、沼液初始浓度等影响因素。结果表明:当沸石投加量为每100mL10g、吸附时间48 h时,最大氨氮去除率可达90.66%,氨氮饱和吸附量可达1.43 mg·g-1,最大总磷去除率可达85.97%,磷饱和吸附量可达0.16 mg·g-1。吸附后的沸石污泥含有大量氮磷元素,是一种优质缓释肥料。Freundlich、Langmuir方程均能较好地解析改性沸石的等温吸附过程,其吸附动力学符合准二级动力学模型,R2均达0.98以上。沸石对猪场沼液中有机态氮磷去除主要基于物理性吸附和沸石中的活性基团与有机官能团所产生的配位络合,无机态氮磷则主要以离子交换及吸附沉淀方式得以去除。

换油条件下变压器油纸绝缘老化寿命评估研究

绝缘油作为变压器油纸绝缘的重要组成部分,其绝缘性能对油纸绝缘有重要影响,变压器通过定期换油清除油中杂质以提高其绝缘性能。为探索换油周期对变压器热老化寿命变化规律的影响,对不同换油周期的变压器油纸绝缘XY模型进行130℃下加速热老化试验,并在第15 d、30 d、45 d、60 d时进行换油前后模型变温介电谱测试、绝缘纸板聚合度测试、绝缘油酸值测试等试验。通过对换油后0.01~100 Hz频率段变温介质损耗曲线的绝缘油活化能与绝缘纸板活化能关系进行分析,提出了一种基于换油后中频段介电谱绝缘纸板活化能计算方法。通过上述计算方法构建老化平移因子,然后结合老化平移因子与二阶动力学模型构建不同换油周期、不同温度下的油纸绝缘结构寿命预测关系式。结果表明:随着换油周期的缩短,油纸绝缘寿命逐渐增加;根据提出的方法得到的油纸绝缘寿命预测结果与实际情况相符,验证了方法的有效性。

一步合成聚苯胺/Fe_3O_4磁性纳米吸附剂去除Cr(Ⅵ)的应用

采用一步加热法合成聚苯胺/Fe_3O_4磁性纳米颗粒(PANI-Fe_3O_4),处理模拟含Cr(Ⅵ)废水,探讨吸附时间和吸附温度对Cr(Ⅵ)去除效果的影响。结果表明,反应时间90 min达到吸附饱和状态,吸附温度25℃时可达到较好的吸附效果。在常温下,Cr(Ⅵ)最大吸附量可达200. 2 mg/g,符合准二级动力学模型和Langmuir等温吸附模型。

含缺陷油气管线结构的可靠性计算

介绍了有关计算含缺陷结构可靠性的一种方法———一次二阶矩可靠性方法 ,并给出了一个含腐蚀缺陷油气管线结构可靠性计算的实例。计算结果表明 ,一次二阶矩可靠性方法与常规Monte Carlo方法相比 ,只须迭代 6次就可求得所需的可靠度 β ,计算效率很高 ,计算结果可精确到 0 0 0 0 1。此外 。

高阶单步拟动力试验算法

由于高阶单步法具有无条件稳定、优良的算法阻尼特性、无超越现象、截断误差为Δt5的特性,已成功地应用于结构地震非线性反应分析、主动半主动及智能振动控制、刚度解析表示的动力反应等分析。该文根据结构拟动力试验的特点,考虑到试验中系统所能达到的精度条件,引入等效剪切刚度的思想,提出了高阶单步拟动力试验算法。单自由度和两自由度数值模拟算例分析以及3层足尺拟动力试验结果,证实了算法的可行性和优越性。