Effect of CaO/SiO_(2) Slag Mass Ratio on Dissolution Rate of Alumina-based Refractory Ceramics

The dissolution of alumina-based refractory ceramics in CaO-Al2O3-SiO_(2)slag melts was performed based on the in-situ observation system of an ultra-high-temperature laser confocal microscope,and the effect of the CaO/SiO_(2)slag mass ratio(C/S ratio)on the dissolution rate of alumina-based refractory ceramics was investigated.The results indicate that the dissolution rate increases with an increase of the C/S ratio and is mainly controlled by diffusion.During the early stage of dissolution,for all C/S ratios,the dissolution process conforms to the classical invariant interface approximation model.During the later stage of dissolution,when the C/S ratio is≥6,the dissolution process is significantly different from the model above because of the formation of a thick interfacial layer,which can be explained by dissolution kinetics.

Silymarin-laden PVP-PEG polymeric composite for enhanced aqueous solubility and dissolution rate: Preparation and in vitro characterization

The aim of this work was to develop, optimize and characterize a silymarin-laden polyvinylpyrrolidone(PVP)-polyethylene glycol(PEG) polymeric composite to resolve low aqueous solubility and dissolution rate problem of the drug. A number of silymarin-laden polymeric formulations were fabricated with different quantities of PVP K-30 and PEG 6000 by the solvent-evaporation method. The effect of PVP K-30 and PEG 6000 on the aqueous solubility and dissolution rate was investigated. The optimized formulation and its constituents were characterized using powder X-ray diffraction(PXRD), differential scanning calorimetry(DSC), scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR) techniques. Both the PEG 6000 and PVP K-30 positively affected the aqueous solubility and dissolution rate of the drug. In particular, a formulation consisting of silymarin, PVP K-30 and PEG 6000(0.25/1.5/1.5, w/w/w) furnished the highest solubility(24.3972.95 mg/mL) and an excellent dissolution profile( $100% in 40 min). The solubility enhancement with this formulation was $ 1150-fold as compared to plain silymarin powder. Moreover, all the constituents existed in the amorphous state in this silymarin-laden PVP-PEG polymeric composite. Accordingly, this formulation might be a promising tool to administer silymarin with an enhanced effect via the oral route.

Effect of Complexation with Hydroxylpropyl-β-Cyclodextrin on Solubility, Dissolution Rate and Chemical Stability of Prostaglandin E1

Aim To study the effect of complexation with hydroxylpmpyl-β-cycledextrin (HP-β-CD) on the solubility, dissolution rate and chemical stability of pmstaglandin E1 (PGE1), thereby providing a basis for preparing a stable solid or aqueous preparation of PGF1 formulated with HP-β-CD. Methods The effect of HP-β-CD on the solubility of PGF1 was studied by phase solubility method. The formation of inclusion complexes of PGE1 with HP-β-CD in the aqueous solution was confirmed by UV spectra, circular dichroism spectroscopy, and that in the solid state by IR spectra and X-ray diffractometry. An solid inclusion complex of PGF1 with HP-β-CD was prepared by lyophilization. The dissolution rate and stability of the inclusion complex were determined and compared with those of PGE1 alone. Meanwhile, the stability of PGF1 aqueous solutions in the presence of HP-β-CD was studied under different pH conditions. Results The solubility of PGF1 increased linearly with increasing HP-β-CD concentration in various pH buffered solutions, showing typical AL-type phase solubility diagrams. The stability and dissolution rate of the solid inclusion complex of PGE1 were significantly increased, compared with those of pure PGE1 . The stability of PGEI in HP-β-CD solutions was also obviously improved under acidic and basic conditions, but the stabilizing effect was absent under neutral conditions. Conclulsions The solubility, dissolution rate and chemical stability of PGE1 are markedly improved by complexation with HP-β-CD. It is quite possible to prepare a stable PGE1 inclusion complex-containing solid dosage forms, but almost impossible to obtain a stable aqueous preparation of PGE1 formulated with HP-β-CD.

Cocrystals of carbamazepine:Structure,mechanical properties,fluorescence properties,solubility,and dissolution rate

Carbamazepine(CBZ)is an anticonvulsant with very low water solubility,presenting as a white crystalline powder with poor mechanical properties and is hard to bend.To enhance CBZ's physicochemical properties,such as water solubility and mechanical properties,we selected six cocrystal coformers(CCFs):nicotinamide(NIC),benzamide(BZM),salicylic acid(SCA),fumaric acid(FMA),trimesic acid(TMA),and hesperetin(HPE).Six CBZ cocrystals were successfully prepared using the solution method.Fourier transform infrared spectroscopy(FT-IR),powder X-ray diffraction(PXRD),differential scanning calorimetry(DSC),and single crystal X-ray diffraction(SCXRD)were used to characterize the crystal structures and gain comprehensive insights into the six cocrystals.The mechanical,fluorescence,and solubility properties of the six cocrystals were tested.The results reveal that most of the prepared cocrystals exhibit improved water solubility and mechanical properties when compared to CBZ.Among them,the dissolution rate of cocrystals excluded from CBZ-HPE has increased by an average of 3 or 4 times compared to CBZ,while CBZ-HPE exhibits superior mechanical properties.Moreover,all six cocrystals possess better fluorescence performance than CBZ.We thoroughly evaluated the mechanical properties of the cocrystals through both experimental and theoretical approaches.This work provides a new direction for studying drug cocrystals to improve the physicochemical properties of drugs.

Experimental Determination of Calcite Dissolution Rates and Equilibrium Concentrations in Deionized Water Approaching Calcite Equilibrium

The calcite dissolution rates at 50-250 ℃ and 20 MPa in deionized water with flow rate varying from 0.2 to 5 mL/min were experimentally measured in a continuous flow column pressure vessel reactor. Equilibrium concentration （Ceq） of calcite dissolution in deionized water at 20 MPa was determined using dissolution data according to the iterative method presented by Jeschke and Dreybrodt. The equilibrium concentrations at 50, 100, 150, 200 and 250 ℃ are 1.84×10^-4, 2.23×10^-4, 2.25×10^-4, 2.31×10^-4 and 2.24×10^-4 mol/L, respectively. The Ceq increases first and then decreases with temperature varying from 50 to 250 ℃ at 20 MPa, and the same variation trend occurs at 10 MPa with lower values. The maximum value （or extremum） of Ceq would increase with temperature at constant pressures. The dissolution reaction of calcite in this experiment is approaching the calcite equilibrium, and the reaction order doesn＇t keep a constant at different temperatures, which could imply that a change of the reac- tion mechanism was occurring. The Arrhenius equation shouldn＇t be used to calculate apparent activation energy using rate constant data at different temperatures when the reaction order or reaction mechanism changed.

Carbonate rock dissolution rates in different landuses and their carbon sink effect

Research on karst processes is important for the determination of their carbon sink potential,as is research into terrestrial ecosystems in karst areas.Solutional denudation rates of soils from three karst spring watersheds supporting different land uses were studied.Solution rates showed a distinct pattern based on land use,with a generally higher rate being recorded in forest use soil.The mean values for tablet dissolution from the cultivated land,shrublands,secondary forest,grassland and primary forest were 4.02,7.0,40.0,20.0,63.5 t km-2 a-1 respectively.Changes in vegetation patterns could improve the size of karst carbon sinks;for example,in this study the carbon sink was 3 times higher in primary forest than in secondary forest soil and 9 times higher than under shrubland,equating to an increase from 5.71-7.02 to 24.86-26.17 t km-2 a-1 from cultivated land or shrub to secondary forest and to primary forest,respectively.

Dissolution rate determination of alumina in molten cryolite-based aluminum electrolyte

Determination of dissolution rate of alumina is one of the classical problems in aluminum electrolysis.A novel method which can measure the dissolution rate of alumina was presented.Effect of factors on dissolution rate of alumina was studied intuitively and roundly using transparent quartz electrobath and image analysis techniques.Images about dissolution process of alumina were taken at an interval of fixed time from transparent quartz electrobath of double rooms.Gabor wavelet transforms were used for extracting and describing the texture features of each image.After subsampling several times,the dissolution rate of alumina was computed using these texture features in local neighborhood of samples.Regression equation of the dissolution rate of alumina was obtained using these dissolution rates.Experiments show that the regression equation of the dissolution rate of alumina is y=-0.000 5x3+0.024 0x2-0.287 3x+ 1.276 7 for Na3AlF6-AlF3-Al2O3-CaF2-LiF-MgF2 system at 920 °C.

碳酸盐岩裂隙溶蚀扩展试验与模拟研究

研究表明碳酸盐岩的溶蚀过程可用溶解速率方程进行表征,但表征的形式存在较大差别,主要体现在远离平衡的欠饱和态下。为进一步确定碳酸盐岩在欠饱和态下的溶解特征及溶蚀速率的表征形式,首先开展了碳酸盐岩裂隙溶蚀试验研究,探讨了CO_(2)及溶液初始Ca^(2+)浓度对溶蚀过程的影响,并基于试验结果构建了欠饱和态下的溶解速率方程;而后采用碳酸盐岩裂隙渗流-溶解耦合模型,通过数值模拟对量化模型的参数进行率定和检验。结果表明:(1)CO_(2)的参与加快了碳酸盐岩的溶蚀扩展,溶液初始Ca^(2+)浓度越高,对碳酸盐岩的溶解抑制程度就越高;(2)CO_(2)作用下碳酸盐岩裂隙溶蚀扩展的平均溶蚀速率增加了1.82~2.29倍;(3)溶液不同初始Ca^(2+)浓度在同等区间流量条件下,蒸馏水为溶蚀溶液的样品中Ca^(2+)浓度差值下降了0.0915mmol/L,溶液初始Ca^(2+)浓度为0.352,0.476,0.581mmol/L的溶蚀溶液中,Ca^(2+)浓度差值分别下降了0.0742,0.0536,0.0474mmol/L;(4)在高度欠饱和状态下溶解动力学由线性速率定律控制,随着溶液中Ca^(2+)浓度的升高,溶解动力学将变为非线性关系,此时Ca^(2+)浓度为0.4倍的平衡时Ca^(2+)浓度。研究结果可为定量评价岩溶发育演化提供数据支撑。

桂皮、八角和花椒中重金属的溶出及健康风险评估

为研究八角、桂皮和花椒中的重金属摄入风险,从主产区采集15份桂皮(广西藤县)、15份八角(广西浦北县)和15份花椒(贵州德江县)样品,采用电感耦合等离子体串联质谱仪测定8种重金属(砷、钡、镉、铬、铜、锰、镍和铅)的含量,结合日常食用习惯,分析了这3种香辛料中的重金属在不同煮沸时间下的溶出情况,采用溶出结果计算其靶标危害指数(THQ)和非致癌风险指数(HI)。结果表明,这3个地区采集的八角、桂皮和花椒样品均未超过GB 2762—2022《食品安全国家标准食品中污染物限量》要求,桂皮中Mn含量要显著高于其他香调料的含量。桂皮和八角中的As,八角中的Ba、Cd、Mn和Ni溶出率超过50%,Mn和Ni在16 h后溶出率超过了95%(分别为95%和96%)。桂皮和花椒的HI值在不同时间的煮沸浸提时间段没有显著性差异(P≥0.05),八角的HI值要显著高于桂皮和花椒(P≤0.05);通过计算发现:无论是单种香辛料摄入单个重金属的THQ值,还是单种香辛料摄入8种重金属的HI值或3种香辛料叠加摄入的HI值,正常摄入来自这些地区的八角、桂皮和花椒不会引起非致癌的健康风险。

铝灰碱法烧结熟料溶出过程及超声协同作用研究

二次铝灰碱法烧结熟料溶出过程是回收氧化铝的重要环节,当溶出过程关键参数控制不当,会造成氧化铝溶出率低、能耗较高。为了提高氧化铝溶出率,了解氧化铝溶出机制,降低溶出过程能耗,探究了二次铝灰碱法焙烧熟料常压溶出过程中温度、时间、液固比与熟料中氧化铝溶出率的关系及熟料中NaAlO_(2)溶出过程动力学,考察了施加超声对氧化铝溶出率的影响。结果表明:熟料溶出过程优化参数为溶出温度为80℃、溶出时间为15 min、液固比(体积质量比,mL/g)为15,氧化铝溶出率可达92.3%;溶出动力学表明,NaAlO_(2)溶出过程受内扩散控制,表观活化能为13.45 kJ/mol;发现施加超声可在相同氧化铝溶出率下降低溶出温度至70℃并缩短溶出时间至9 min。该研究结果可为二次铝灰碱性焙烧熟料溶出过程降低能耗和提高效率提供新的理论参考和基础数据。

酸化对高阶煤不同层理方向增透效果影响研究

为了研究酸化对寺河矿高阶煤垂直、平行两个层理方向的增透效果,开展了多组分酸煤粉和煤柱溶蚀试验,优选出了合适的酸液体系,分析了两个层理方向煤柱不同酸化时长下的溶蚀效果,并进行了两个层理方向煤柱的煤岩三轴吸附-解吸-渗流试验和低场核磁共振试验,对比了酸化前后的渗透率、孔隙度、孔径分布变化。结果表明:(1)寺河矿酸化选用质量分数2%HCl+2%CH3COOH+5%HF的酸液配比溶蚀效果最优;(2)酸化使垂直层理方向煤柱的孔隙率增幅更大,而平行层理方向煤柱达到最大增幅用时更短;(3)酸化后两个层理方向煤柱的渗透率、孔隙度均提升,垂直层理方向煤柱孔隙度增幅更大,渗透率增幅则小于平行层理方向煤柱,且二者的渗透率增幅都在滑脱效应拐点处最小;(4)酸化使两个层理方向煤柱的瓦斯吸附孔占比下降,其中平行层理方向煤柱降比更大,且酸化前后中大孔占比也都更高;确定了寺河矿酸化后以煤样平行层理方向作为钻孔瓦斯抽采方向能更好地提高瓦斯抽采率。

CO_(2)浓度及配比对焦炭溶损特性影响

研究块焦、粉焦混合焦炭在CO_(2)气氛下的反应特性可有效提高干熄焦质量、降低溶损率,故采用自制高温焦炭反应测定装置,研究不同粒径配比及不同浓度CO_(2)条件下的碳素溶损反应,结合光学显微镜分析及Coats-Redfern法探讨了混合不同粒径干熄焦的溶损机理。结果表明,不同浓度下粉焦比例增加,粉焦溶损率为混合焦炭溶损率的0.7~0.9倍,较多CO_(2)与粉焦发生碳溶反应,导致块焦-粉焦混合焦炭溶损率随粉焦比例增加而增加。但在不同浓度下块焦和粉焦的各向同性组织含量降低而各向异性组织含量明显增加,其中,粉焦各向异性指数高于块焦,且平均增长4%,其反应活性也高于块焦,反应活化能随CO_(2)浓度、粉焦比例的增加而降低;且同一浓度下,焦炭中粉焦比例越多,碳溶反应越易进行。在低浓度下,粉焦比例对混合焦炭溶损率有显著影响,随粉焦比例增加活化能降幅最大为30%。研究结果可为进一步降低干熄焦溶损率提供理论依据。

依鲁替尼纳米晶的制备工艺研究

为改善依鲁替尼(IBR)的水溶性和溶出度,采用湿法介质研磨法制备了依鲁替尼纳米晶(IBR-NC),采用单因素实验优化了IBR-NC的制备工艺,并通过粒径分析、扫描电镜(SEM)、X-射线粉末衍射(XRPD)分析、差示扫描量热(DSC)分析及溶出度实验对IBR-NC的质量进行了评价。结果表明,以PVP-K30-SDS为稳定剂,在物料比(IBR、PVP-K30、SDS的质量比)为10∶4∶1、IBR用量为120 mg、氧化锆珠规格为0.3 mm、氧化锆珠用量为40 g、研磨转速为150 r·min^(-1)、研磨时间为2.0 h的最优条件下,制备的IBR-NC的粒径为(224.7±5.7)nm、PDI为0.151±0.017,累积溶出率在10 min能达到99.49%,溶出效果良好,且放置90 d后依然具有良好的溶出性质。

不同黏合剂对网箱养殖刺参饲料溶散速率的影响

开展了刺参颗粒饲料中添加不同种类黏合剂对其在水中溶散性能的影响试验。设置4个饲料试验组,分别添加瓜儿豆胶、海藻酸钠、黄原胶和明胶4种黏合剂,1个饲料对照组,不加黏合剂,每组设3个平行。结果表明,对照组在试验6 h后,饲料已完全溶散,海藻酸钠组在48 h溶散比达到98.56%,黄原胶和瓜儿豆胶组均在96 h完全溶散,明胶组则在174 h后才完全溶散。海藻酸钠组溶散速率(2.05%/h)显著高于其他各组(P<0.05),黄原胶和瓜儿豆胶组溶散速率(1.04%/h和1.02%/h)次之,明胶组的溶散速率(0.56%/h)显著低于其他各组(P<0.05)。指出,在刺参颗粒饲料中添加黏合剂,能有效提高饲料在水中的稳定性,其中明胶对饲料的稳定性最好。

四嗪二甲酰胺环糊精包合物制备研究

目的:制备四嗪二甲酰胺(ZGDHu-1)环糊精包合物,对其质量进行表征。方法:采用饱和水溶液法制备四嗪二甲酰胺的甲基-β-环糊精包合物体系,通过高效液相色谱法检测药物含量,通过扫描电镜、差示扫描量热分析、包合率和溶出度对包合物质量进行考察。结果:四嗪二甲酰胺含量检测在1.078~107.9μg·mL^(-1)范围内线性关系良好,扫描电镜观察和差示扫描量热分析表明四嗪二甲酰胺以无定型状态被包埋在辅料空腔内,包合物中四嗪二甲酰胺的平均包合率为87.19%,包合物体系显著提高了四嗪二甲酰胺的溶出度,80 min累积溶出度为82.60%。结论:四嗪二甲酰胺环糊精包合物制备方法简便,包合率高,对体外溶出具有良好的改善效果。

苦参碱固体分散体的制备及体外溶出研究

为提高苦参碱(matrine,MAT)的缓释性能,延长体外释药时间,本研究以苦参碱为目标药物,以乙基纤维素(EC)为载体,利用球磨法制备苦参碱无定形固体分散体(MAT-ASD),通过粉末X射线衍射(PXRD)、差示扫描量热(DSC)、傅里叶红外光谱(FT-IR)对其进行表征,并考察其体外释放特性。结果显示,利用该方法成功制备了MAT-ASD(药物与载体比例为1∶9),粉末X射线衍射中无苦参碱的晶体特征峰,差示扫描量热分析显示无苦参碱晶体吸热峰,傅里叶红外光谱扫描显示苦参碱与乙基纤维素之间存在相互作用,可能产生了分子间氢键。体外溶出结果显示,在0.25 h内苦参碱的累积溶出率几乎达100%,而MAT-ASD的累积溶出率仅为56.29%,在6 h时MAT-ASD的累积溶出率为95.22%。结果提示,以乙基纤维素为载体,利用球磨法可成功制备MAT-ASD,并可有效延长苦参碱的体外释药性能,为苦参碱缓释制剂的开发奠定了基础。

生态保护修复对碳酸盐岩溶蚀速率的影响——以重庆市为例

岩溶区矿山生态修复、石漠化治理等生态保护修复工程,不仅改善了区内生态环境,而且有利于促进土壤、岩溶固碳增汇,对实现“双碳”目标具有重要意义。以重庆主城北碚矿山生态修复、渝东北巫山石漠化治理区等为例,通过野外标准溶蚀试片实验法和土壤取样测试分析法,研究不同生态保护修复措施下土壤碳库、碳酸盐岩溶蚀速率等变化特征,探讨不同生态修复方式对碳酸盐岩溶蚀速率的影响。结果表明:灰岩矿山修复区、石漠化治理区,土壤无机碳(SIC)含量较高,约为土壤有机碳(SOC)的4.5倍,且对碳酸盐岩溶蚀速率有一定的抑制作用;修复时间越长,土壤有机碳(SOC)含量越高,但SOC含量与碳酸盐岩溶蚀速率的相关性不显著;从夏季(监测期7、8月遭受极端高温干旱)至秋、冬、春季,土下及地表试片溶蚀速率明显增大;不同生态保护修复方式或植被恢复类型,碳酸盐岩溶蚀速率明显不同,北碚矿山修复区月桂林>草灌从(橘树)>草灌从(桃树)>花椒树>李子树,巫山生态修复区石漠化治理林地>封山育林林地>石漠化治理果园。

低渗透油田生物酶复合中性解堵剂性能研究

针对低渗透CQ油田有机无机复合垢的组成特点,研制了一种以生物酶、生物表面活性剂、螯合酸为主要成分的生物酶复合中性解堵剂,并对其性能进行了评价。结果表明,CQ油田有机无机复合垢中无机垢、有机垢占比分别为80.40%、19.60%;无机垢胶结不强,结构松散,主要成分为碳酸钙和硫化亚铁;生物酶复合中性解堵剂与CQ油田地层水配伍性良好,生物酶复合中性解堵剂体系密度为1.189 g·mL^(-1),表面张力为28.43 mN·m^(-1),72 h腐蚀速率最高为0.033 5 g·m^(-2)·h^(-1);生物酶复合中性解堵剂能将有机无机复合垢有效溶解,12 h溶垢率达85.9%。

特种臭氧催化剂制备及处理煤化工生化出水研究

为高效去除煤化工生化出水中的有机物,采用浸渍法制备非均相臭氧催化剂,用于催化臭氧氧化处理煤化工生化出水。先以模拟废水为处理对象,分析了催化剂载体种类、活性组分种类及配比、浸渍时间、焙烧温度及焙烧时间等因素对催化剂催化臭氧氧化效果的影响,确定最佳臭氧催化剂组分及制备工艺,之后对优化条件下制备的催化剂开展物性分析,分析了催化剂的表观形貌、微观结构及成分,最后采用实际生化出水开展了催化剂的稳定性评价。结果表明:采用浸渍法,在浸渍时间24 h、焙烧温度550℃、焙烧时间5 h条件下,以γ-Al_(2)O_(3)为载体、以n(Mn)∶n(Fe)∶n(Cu)=2∶1∶1作为活性组分配比制备得到的非均相臭氧催化剂具有较优的催化臭氧氧化性能,实验条件下将其用于催化臭氧氧化处理模拟废水中的难降解有机物,COD去除率高达64.6%;所制备催化剂具有较高的比表面积及介孔,用于中试处理实际煤化工生化出水时结构稳定,应用效果稳定,吨水处理运行费用为4.57元。