Interconnected and high cycling stability polypyrrole supercapacitors using cellulose nanocrystals and commonly used inorganic salts as dopants

Polypyrrole(PPy)is wildly used as electrode material in supercapacitors due to its high conductivity,low cost,ease of handling,and ease of fabrication.However,limited capacitance and poor cycling stability hinder its practical application.After developing carboxylated cellulose nanocrystals(CNC-COO^(-))as immobile dopants for PPy to improve its cycling stability,we investigated the effect of different commonly used salts(KCl,NaCl,KBr,and NaClO_(4))as dopants during electrode fabrication by electropolymerization.The film’s capacitance increased from 160.6 to 183.4 F g^(-1)after adding a combination of KCl and NaClO_(4) into the electrodeposition electrolyte.More importantly,the porous and interconnected PPy/CNC-COO^(-)-Cl-(Cl O_(4)^(-))_0.5 electrode film exhibited an excellent capacitance of 125.0 F g^(-1)(0.78 F cm^(-2))at a high current density of 2.0 Ag^(-1)(20 m A cm^(-2),allowing charging in less than 1 min),increasing almost 204%over PPy/CNC-COO-films.A symmetric PPy/CNC-COO^(-)-Cl-(ClO_(4)^(-))_0.5 supercapacitor retained its full capacitance after 5000 cycles,and displayed a high energy density of 5.2 Wh kg^(-1)at a power density of 25.4 W kg^(-1)(34.5μWh cm^(-2) at 1752.3μW cm^(-2)).These results reveal that the porous structure formed by doping with CNC-COO-and inorganic salts opens up more active reaction areas to store charges in PPy-based films as the stiff and ribbon-like CNC-COO-as permanent dopants improve the strength and stability of PPy-based films.Our demonstration provides a simple and practical way to deposit PPy based supercapacitors with high capacitance,fast charging,and excellent cycling stability.

Effect of inorganic salt on the thermal degradation of nitrocellulose and reaction mechanism of its mixture

In this study,to better understand the reaction mechanism between inorganic salts and nitrocellulose,CaCO_(3) and Li_(2)CO_(3) were evaluated with respect to their effects on the thermal degradation of NC in nitrogen atmosphere using TG/DSC at three different heating rates(2,5,10 K/min).The numerical relationship between activation energy(E)and conversion rate was obtained by FWO and KAS method,and it was discovered that CaCO_(3) could improve the thermal stability of NC.Activation energy values were calculated by Kissinger method,and it was found that NC that contain Li2CO3had the highest activation energy while NC containing CaCO3had the lowest E value.By combining the thermal analysis data with Malek method,the most probable mechanism model of thermal degradation is obtained as Sesták-Berggren model,which expression is f(α)=α^(m)(1-α)^(n).As a result of this study,there are certain guiding principles that can be applied to the pyrolysis reaction model and to the actual production process of nitrocellulose.

The effect of inorganic salt precipitation on oil recovery during CO2 flooding:A case study of Chang 8 block in Changqing oilfield,NW China

Static experiments and dynamic displacement experiments were conducted to quantitatively determine the amount of precipitate generated by the CO_(2)-formation water reaction at different temperatures,pressures,and scaling ion concentrations during CO_(2) flooding in the Chang 8 block of Changqing Oilfield,the influence of precipitate on the physical properties of reservoirs was investigated,and the corresponding mathematical characterization model was established.The mathematical characterization equation was used to correct the numerical simulation model of E300 module in Eclipse software.The distribution pattern of inorganic salt precipitates during continuous CO_(2) flooding in Chang 8 block was simulated,and the influence of inorganic salt precipitates on oil recovery was predicted.The inorganic salt precipitate generated during CO_(2)-formation water reaction was mainly CaCO_(3),and the pressure difference and scaling ion concentration were proportional to the amount of precipitate generated,while the temperature was inversely proportional to the amount of precipitate.The rate of core porosity change before and after CO_(2) flooding was positively correlated with temperature and flooding pressure difference.The core porosity increase in the CO_(2)-formation water-core reaction experiment was always lower than that of CO_(2)-distilled water-core reaction experiment because of precipitation.The area around the production wells had the most precipitates generated with the injection of CO_(2).The oil field became poor in development because of the widely distributed precipitate and the recovery decreased to 33.45% from 37.64% after 20-year-CO_(2) flooding when considering of precipitation.

Separation of Water from Extra-viscous Oil under Microwave Radiation in the Presence of Inorganic Salts

Removal of water contained in extra-viscous crude oil is quite difficult because of the high viscosity and high resins content of heavy oil.The microwave technology was introduced for the separation of water from high-viscosity crude oil in the presence of sodium acetate.The decrease in zeta-potential of interface and the viscosity of crude oil are responsible for the accelerated separation of water under microwave irradiation.The influences of the concentration of sodium acetate in sample,irradiation pressure,irradiation time and irradiation power on the separation efficiency were investigated.The optimum technological condition for the refining process was determined.Upon treating the sample 1 (with a water concentration of 50%),the water removal rate was 98.44%,when the optimum conditions were identified to be a sodium acetate concentration of 2%,an irradiation pressure of 0.1 MPa,an irradiation time of 2 min,and an irradiation power of 225 W,with the recovery of sodium acetate reaching 97.88%.Upon treating the sample 2 (the concentration of water was 20%),the water removal rate was 93.85%,when the optimum conditions were determined to be a sodium acetate concentration of 3%,an irradiation pressure of 0.1 MPa,an irradiation time of 4 min,and an irradiation power of 375 W,with the recovery of sodium acetate reaching 93.54%.By using this method,the dehydration efficiency was increased rapidly.

Influence of Inorganic Salts on the Adsorption of Cationically Modified Starch to Fibers

The article is focused on the influence of inorganic salts on the adsorption of cationically modified starch to fibers. Results show that low concentrations of inorganic salts usually affect the process of adsorption in a positive way. Adsorption efficiency at higher concentrations, however, depends on the type of inorganic salts as well as the sequence of adding inorganic salts and starch to paper suspension.

Pore Structure of Cement Pastes Mixed with Inorganic Salts

The influence of salts on concrete durability,pore structure of cement pastes with inorganic salts,including CaCl2,NaCl,Na2SO4,NaNO2,Ca(NO3)2 and Ca(NO2)2,was studied through mercury intrusion porosimetry (MIP),and hydration degree of each paste was also tested.The results show that porosity of the paste with inorganic salt cured for 3 d or 28 d was related with its hydration degree.For the pore size distribution,the pores smaller than 50 nm in paste with salts cured for 3 d increased;the amount of pores larger than 100 nm increased because of the addition of Ca (NO3)2 at 3 d,but these coarse pores turned into fine pores and reduced significantly at 28 d;coarse pores lager than 1000 nm in cement pastes containing NaCl and Na2SO4 increased.

滨海盐田土壤碳时空分布特征及碳收支

滨海盐田存在土壤盐碱化、瘠薄与有机碳含量低等障碍问题,有关滨海盐田土壤碳方面的系统研究目前依然缺乏典型实例剖析。为了揭示滨海盐田以及用地类型发生转变后土壤的有机碳时空分布特征、影响因素及碳收支,选取江苏省连云港市徐圩新区和青口盐场的土壤为研究对象,采取表层(0~20 cm,2004年和2019年两期数据)土壤及深层(150~200 cm,2004年一期数据)土壤样品,进行了土壤有机碳(SOC)、总碳(TC)及总氮(TN)的测试。结果表明,SOC储量呈增加趋势,碳汇区面积占比69.4%,碳源区占比30.6%,不同用地类型SOC含量与平均固碳速率差异较大。2004年表层SOC含量分布在低、中两个等级区间,2019年SOC含量在中等级分布频率最高。近15年盐田1区(用地类型保持不变)SOC含量增加了0.12%,盐田2区(耕地)SOC含量增加了0.42%,盐田3区(建设用地)SOC含量增加了0.13%。平均固碳速率最高值出现在耕地类型,数值达到了5.83×10^(4)kg·km^(-2)·a^(-1)。盐田1区土壤有机碳的分解主要通过微生物的异氧呼吸途径来实现,有机碳的有氧矿化主要通过真菌与细菌的有氧矿化来实现。滨海盐土具有高含量的SO_(4)^(2-)与Ca~(2+),有机碳的厌氧矿化主要通过SO_(4)^(2-)还原来实现,因此无机碳的增加速率较大,达到3.64 g·m^(-2)·a^(-1)。盐田1区两期数据SOC/TN平均值均为9.9,说明土壤环境稳定。盐田3区SOC/TN稍有下降,推测原因是土壤微生物量及酶活性提高导致SOC的矿化速率增加。在环境问题日益严重和土壤质量趋向恶化的情况下,本文的研究成果为滨海盐田及其土地利用类型转变后的土壤碳循环研究提供了新的基础依据。

保鲜剂对杜鹃切花采后品质的影响

为探究不同保鲜剂对杜鹃切花采后观赏品质的影响,并筛选出杜鹃切花的适合保鲜剂配方,以东洋杜鹃品种‘红元宝’为研究对象,采用不同保鲜剂对其进行瓶插处理,测定不同处理对切花瓶插寿命、鲜质量变化、水分平衡、质膜稳定性等生理指标和观赏品质的影响。结果表明:100~300 mg/L 8-羟基喹啉对‘红元宝’切花的保鲜具有积极作用,可有效延缓花瓣边缘卷曲和萎蔫,促进花径的增大并保持更长的开花时间(18 d),维持切花体内水分平衡,减缓其鲜质量变化及质膜透性的增加。而0.2~0.6 mmol/L硫代硫酸银处理不利于‘红元宝’杜鹃切花采后品质的保持,反而加剧了切花的衰老。经筛选,确定30 g/L蔗糖+200 mg/L 8-羟基喹啉为‘红元宝’杜鹃切花的最适保鲜剂。

FeSO_(4)/K_(2)S_(2)O_(8)对微细粒高黏煤泥的化学调控助滤影响

含大量高灰细泥的煤泥水在沉降浓缩阶段通常会添加大量高分子聚丙烯酰胺(PAM),加速细粒煤的沉降,但PAM的过量使用使浓缩机底流更加黏稠,导致压滤周期延长。通过向含大量高分子PAM的矿浆中添加无机盐FeSO_(4)、K_(2)S_(2)O_(8)溶液,进行不同药剂用量下煤泥的压滤试验,对药剂添加前后PAM溶液和含PAM矿浆的黏度、颗粒表面电性及颗粒团聚形态进行测试分析,探讨FeSO_(4)、K_(2)S_(2)O_(8)的作用机理。结果表明:FeSO_(4)、K_(2)S_(2)O_(8)可降解矿浆中的大分子PAM,降低矿浆黏度,形成松散的大絮体,提高速度,缩短压滤周期,降低滤饼含水率。由于FeSO_(4)兼具对PAM的化学降解和对微细颗粒的凝聚作用,其助滤效果优于K_(2)S_(2)O_(8)。当FeSO_(4)用量为1000 g/t时矿浆黏度降低482 mPa·s,压滤时间缩短70.97%,滤饼含水率降低2.31%。FeSO_(4)价廉易得,可在选煤厂高泥化煤泥脱水助滤上发挥积极作用。

基于圆柱封装单元的水合盐相变储热填充床的储释特性实验研究

水合盐相变储热技术具有储热密度高、成本低等优势,在清洁供暖中具有广阔应用前景。本研究设计并搭建了以三水合乙酸钠作为储热材料,以圆柱形相变材料封装单元作为基础单元的填充床相变储热装置。通过实验研究填充床储热装置的运行特性,研究了流量和储热温度对装置的储释热用时、出口温度、热效率及储热密度的影响。实验结果表明:提高储热温度和增大流量可缩短储热用时、提升热效率和储热密度。储热装置的热效率可达94.73%,储能密度可达71.77 kW·h/m~3。

马来酸酐与烯丙基磺酸钠共聚物的聚合过程及阻垢性能

为了分析马来酸酐(MA)与烯丙基磺酸钠(SAS)聚合过程的影响因素,在配方和工艺基本不变的情况下,设计了两种变量:中和度和引发剂加量。通过改变其中一个变量,合成了一系列MA/SAS共聚物,采用核磁共振波谱仪和凝胶渗透色谱仪对产物进行了表征。结果表明,MA与SAS共聚活性良好,中和度不超过100%时(相对于MA的物质的量分数),少量引发剂加量(2.4 g过硫酸钠)下就有较高的单体转化率,但仍有6%~8%的单体未聚合。剩余单体的种类和数量与中和度以及引发剂加量息息相关。MA在水溶液中部分水解成了马来酸,尽管马来酸数量较少,但其聚合活性相对较差,导致共聚物的分子量呈双峰分布。添加碱可以中和马来酸,当中和度不超过100%时,马来酸主要变为具有较好聚合活性的马来酸单钠盐,间接促进了MA类单体的聚合;当中和度为200%时,马来酸主要变为马来酸二钠盐,其聚合活性相对较差,严重阻碍了聚合;未中和以及中和度为100%时,需7.0~7.2 g引发剂才能将单体全部转化,而在适当的中和度(约20%)下,用少量引发剂(4.0~4.2 g)就可以获得聚合较完全的共聚物,节约了大约40%的引发剂用量。用较佳条件下合成的MA/SAS共聚物对碳酸钙、磷酸钙和硫酸钙的静态阻垢性能进行了研究,共聚物表现出良好的阻磷酸钙垢和阻硫酸钙垢、较好的阻碳酸钙垢性能,对应的最大阻垢率分别为94.38%、100.00%、59.03%。

无机盐协同表面活性剂对煤尘保湿性影响

为保障煤矿安全生产和工人健康,煤矿井下主要采取的防尘手段是湿式除尘和化学抑尘。通过保水性实验探究无机盐与表面活性剂溶液各自及协同作用下的抑尘保湿性效果。实验结果表明:由于四种表面活性剂的分子结构和性质不同,形成分子层的稳定性和厚度不同,十二烷基苯磺酸钠溶液(SDBS)的保湿性最强,聚乙二醇对异辛基苯基醚溶液(Triton X-100)的保湿性最弱。当表面活性剂SDS与SDBS溶液质量分数分别为0.24%、0.04%,无机盐K_(2)SO_(4)的浓度0.9mol/L,且SDS与SDBS比例为5∶5,SDS+SDBS的混合溶液与K_(2)SO_(4)比例同样为5∶5时,煤尘水分散失最少,复合溶液润湿保湿性能最佳。硫酸钾溶液对复合溶液的疏水端产生析出作用,导致煤尘疏水端的疏水作用增强,更多表面活性剂分子逃逸水相后向液-气界面聚集,从而降低溶液的表面张力。

有机小分子/无机盐膜分离影响因素及改性

在碳达峰、碳中和的“双碳”背景下,污水处理与资源化技术必将朝着“绿色低碳化”方向发展,而有机小分子和无机盐的分离成为目前制约废水资源化利用的原因之一.膜技术可应用于有机小分子和无机盐的分离,但有机小分子/无机盐膜分离的影响因素尚未得出一致结论.本文从工业废水资源化利用背景出发,以有机小分子和无机盐膜分离为研究对象,综述了影响膜分离的主要因素,进而对能提升膜性能的策略进行介绍,同时指出膜孔径和膜表面的荷电性是影响膜分离效果的主要因素,高亲水性、荷正电型疏松纳滤膜是未来有机小分子/无机盐分离膜的主要发展方向.

新型钙镁硅复合无机材料对盐胁迫下小麦幼苗生长的影响

为确定新型钙镁硅复合无机材料(IM)对盐(NaCl)胁迫下小麦幼苗生长的影响,采用液培法,通过在营养液中添加IM,制备了ρ(IM)=3.15,6.30,9.45,12.60,15.75 g·L^(-1)的5种培养液,进行了不同添加量的IM对盐胁迫下小麦幼苗生长与生理特性影响的试验。结果表明:盐胁迫显著抑制了小麦幼苗的生长,添加IM能有效缓解小麦幼苗的盐胁迫效应,其中以ρ(IM)=12.60 g·L^(-1)的处理能显著促进盐胁迫下小麦幼苗的生长,降低盐胁迫下小麦幼苗根系与叶片的丙二醛质量摩尔浓度和超氧阴离子产生速率,增加叶片和根系的可溶性蛋白质量分数和抗氧化酶活性,并显著提高游离脯氨酸质量分数。

基于无机水合盐相变材料的相变蓄冷新风机实验研究

新风系统提高了空气质量,但其温度波动增加了空调系统的负担。相变材料能够利用低品位冷源进行蓄冷,控制新风温度波动。本研究将性能优异的无机复合相变材料与新风机耦合以搭建相变新风机,探究了18、20、22℃的冷水工况下相变新风机的蓄冷性能,发现夜间高温冷源能够满足蓄冷要求,利用相变储热的方式转移用电高峰;此外,相变蓄冷模块能够将28℃的新风温度降低2.4~3℃;基于峰谷电价政策,该装置充分利用电价差可节约54.8%的电力成本。

一种基于蛭石的多维度改性研究

基于蛭石特有的层状结构及高温膨胀特性,研究不同浓度、不同种类的无机盐添加剂对不同粒径蛭石的改性影响,从多维度提高改性蛭石高温下的膨胀倍数,并进行微观形貌和物相组成分析。研究结果表明:在相同温度条件下,添加NaHCO_(3)和KCl无机盐的改性蛭石体积膨胀率高于未改性蛭石。当添加相同浓度的NaHCO_(3)和KCl时,随着蛭石粒径从0.2 mm增加到0.8 mm,在100—900℃温度范围内,改性蛭石的体积膨胀倍数随温度升高而增加,随粒径增加而增加,且添加KCl的改性效果优于添加NaHCO_(3)。随着这2种无机盐添加剂浓度的逐渐增加,改性蛭石的膨胀倍数均呈现先增加后降低的趋势。

Ca^(2+)介导的月桂酰甲基牛磺酸钠相行为研究

为探究高价无机盐对阴离子表面活性剂月桂酰甲基牛磺酸钠(SMLT)溶液的表面活性和相行为的影响,考察了Ca^(2+)浓度对SMLT溶液的表面张力和不同SMLT/Ca^(2+)摩尔比对SMLT/水二元体系的相行为影响。结果表明,加入适量的Ca^(2+)对其表面活性影响显著,当Ca^(2+)浓度从0增加至0.1 mol/L时,cmc从8.0×10^(-3)mol/L降至8.0×10^(-4)mol/L,γ_(cmc)从36.00 mN/m降至31.45 mN/m。同时,在SMLT溶液中加入Ca^(2+),SMLT/水体系的二元相图出现胶束溶液相区、蠕虫胶束相区、六角束液晶相区、层状液晶相区和胶束-晶体相区,原有的双水相区消失,胶束-晶体区变大。在考察Ca^(2+)浓度对SMLT溶液黏度的影响时,发现当SMLT/Ca^(2+)的摩尔比为1时,SMLT溶液增黏效果明显,摩尔比为0.6时溶液析出固体。选择质量分数为20%的SMLT溶液进行流变性能测定,根据样品流变曲线,发现其具有剪切变稀的现象,冷冻透射电镜显示有蠕虫胶束的形成。