Effect of phosphogypsum on saline-alkalinity and aggregate stability of bauxite residue

A column experiment was conducted to investigate the effect of phosphogypsum (PG) on the saline- alkalinity, and aggregate stability of bauxite residue. Results showed that: with increasing leaching time, the concentrations of saline-alkali ions decreased while the concentration increased in bauxite residue leachate; compared with CK (control group) treatment, pH, electric conductivity (EC), exchangeable sodium percentage (ESP), sodium absorption ratio (SAR), and exchangeable Na⁺ content of bauxite residue were reduced following PG treatment; average particle sizes in aggregates following CK and PG treatments were determined to be 155 and 193 nm, respectively. SR-μCT test results also confirmed that bauxite residue following PG treatment acquired larger aggregates and larger pore diameter. These results indicate that the PG treatment could significantly modulate the saline-alkalinity, and simultaneously enhance aggregate stability of bauxite residue, which provides a facile approach to reclaim bauxite residue disposal areas.     

Development of Phospholipids Vesicular Nanocarrier for Topical Delivery of Tea Tree Oil in Management of Atopic Dermatitis Using BALB/c Mice Model

This work aims to develop and evaluate the efficacy of tea tree oil (TTO) ethosomal cream with improved deposition in skin layers for treatment of atopic dermatitis (AD). Ethosomes of TTO are developed using phosphatidylcholine (2% and 3% w/v) and ethanol (20%, 30%, and 40% w/v). Ethosomes are evaluated for percent entrapment efficiency (%EE), vesicle size, zeta potential, and in vitro drug diffusion. Ethosomal creams with optimized ethosomal dispersion are developed and evaluated for physicochemical parameters, thermal stability, ex vivo permeation, skin retention, and in vitro cytotoxicity using HaCat skin cell lines in comparison to conventional creams of TTO. In vivo investigations of optimized creams are performed using BALB/c mice model. The %EE, vesicle size, and zeta potential for optimized ethosomes are found to be 76.19 ± 3.26%, 333.6 nm, and –35.3 mV, respectively. Ethosomal creams showed higher deposition in the epidermis and dermis. The optimized creams are non-cytotoxic to HaCat cell lines. The creams significantly reduce the inflammatory response by decreasing the clinical score and infiltration of white blood cells, eosinophils, and IgE antibodies. Overall efficacy of ethosomal cream is higher than conventional cream. In conclusion, optimized ethosomal cream of TTO shows good efficacy for treatment of AD. Practical applications : The method used for the formulation of ethosomes is simple and can be easily scaled up on the industrial level. The loading of TTO within ethosomes can increase the efficiency by enhanced drug deposition in the epidermis and might also improve its stability against oxidative degradation. Topical ethosomal cream of TTO can improve patient compliance by avoidance of adverse effects linked with corticosteroids and could be a possible complementary or alternative therapy in management of AD.     

A comparative study on the effect of carbon-based and ceramic additives on the properties of fiber reinforced polymer matrix composites for high temperature applications

Ablative composites have been in use for thermal protection of space vehicles for decades. Carbon-phenolic composites have proven to perform exceptionally well in these applications. However with development in aerospace industry their performance needs improvement. In this field, different carbon-based and ceramic additives have been introduced into ablative composite systems. This review article gives a comparative analysis of researches done in this field in the recent past. Density, ablative, thermal and mechanical properties of ablative composites with different ultra-high temperature ceramic particles i.e. ZrSi₂, Cenosphere, nano-SiO₂, BN etc. and carbon-based nanoparticles i.e. CNTs, nano-Diamonds, Graphene oxide etc. used as additives, have been compared and discussed. Emphasis is put on carbon-phenolic composite systems although some epoxy matrix systems have also been discussed for comparison.     

金银花中有机磷农药残留分析及其冲泡过程迁移模型研究

为确保消费者饮茶安全,建立了QuEChERS-GC-MS/MS快速测定金银花和其茶汤中6种有机磷农药(对硫磷、倍硫磷、特丁硫磷、治螟磷、丙溴磷、灭线磷)残留的检测方法。金银花和茶汤分别经乙腈和乙酸乙酯提取、盐析离心、混合净化剂(10 mg MWCNTs、15 mg PSA、150 mg无水硫酸镁)净化、0.22μm滤膜过滤后,供GC-MS/MS检测。结果表明:金银花和茶汤中,有机磷农药在1～1 000μkg和1～1 000μg/L呈现良好的线性关系,R~20.991;在4个添加水平下,回收率在67.2%～110.3%,相对标准偏差小于19%(n=6);金银花和茶汤中,有机磷农药定量限分别为1μg/kg和1μg/L。在此基础上,深入研究了金银花在冲泡过程中6种有机磷农药的迁移预测模型,表明农药迁移率(TR)与农药的正辛醇-水分配系数(Kow)关联性较大,由此获得预测模型为lg TR=-0.536 2 1g Kow+3.915 2(lg Kow3),R~2=0.914,拟合度较好;而农药迁移率与水溶解度(Ws)并未表示出关联性。该检测方法和迁移模型的建立将有利于更深层次认知农药化学污染物在金银花浸泡过程中的迁移行为,以期为制定金银花中有机磷农药最大残留限量标准提供科学依据和技术支撑。     

陈皮与普洱茶总黄酮的协同抗氧化作用研究

以大红柑柑普茶为原料,应用超声辅助法分别提取陈皮和普洱茶中的总黄酮,提取液经AB-8大孔树脂纯化,旋蒸浓缩得到待测液。将陈皮、普洱茶总黄酮按照浓度比3∶1、1∶1、1∶3混合,测定样品总黄酮溶液和VC对·OH、ABTS^+·和DPPH自由基清除能力和总还原力。结果表明,陈皮和普洱茶总黄酮均有较好的抗氧化作用,各复配组自由基清除率的IC50 mix均小于IC50add且在95%置信区间内有显著性差异,陈皮和普洱茶总黄酮相互作用指数(γ)在各组中均小于1,表明陈皮和普洱茶总黄酮具有协同抗氧化作用。     

Migration and distribution of saline ions in bauxite residue during water leaching

Bauxite residue, a highly saline solid waste produced from digestion of bauxite for alumina production, is hazardous to the environment and restricts vegetation establishment in bauxite residue disposal areas. A novel water leaching process proposed here was used to investigate the dynamic migration and vertical distribution of saline ions in bauxite residue. The results show that water leaching significantly reduced the salinity of bauxite residue, leaching both saline cations Na⁺, K⁺, Ca²⁺ and anions CO^2?₃, SO^2?₄, HCO^?₃. Na⁺ and K⁺ migrated from 40–50 to 20–30 cm of the column, presenting a high migration capacity. The migration capacity of Ca²⁺ was lower and accumulated at 30–40 cm of the column. CO^2?₃ initially distributed at 20–30 cm of the column, subsequently transported to 30–40 cm of the column, and finally returned to 20–30 cm of the column along with evaporation. SO^2?₄ was originally distributed at 40–50 cm, but finally migrated to 20–30 cm of the column. Nevertheless, HCO^?₃ remained at the bottom of the column, and its migratory was less affected by evaporation.     

检测仪器及消解方式对罗布麻微量元素检测效果的影响

目的 探索罗布麻微量元素适宜的检测条件。方法 以新疆产罗布麻和白麻叶及其制品罗布麻茶为实验材料, 比较了电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)和电感耦合等离子体原子发射光谱法(inductively coupled plasma atomic emission spectrometry, ICP-AES)2种仪器对其Li、B、Cr、Fe、Mn、Cu、Zn、Se和Sr 9种微量元素的检测效果, 同时对比了3种不同的湿法消解方式对检测结果的影响。结果 采用不同酸解液的3种湿法消解方法, 硝酸/过氧化氢消解液处理条件较温和, 元素损失量较少, 检测结果稍高于浓硝酸/高氯酸消解液处理的结果, 但所耗消解时间更长。对于易挥发元素Se, 选用酸性和氧化性较弱的硝酸/过氧化氢消解液更适宜。在本试验条件下, 罗布麻体内的Li和Cr 2种微量元素不宜采用ICP-AES仪器检测, 可选用ICP-MS, 而对于难电离元素Se则正好相反。结论 检测罗布麻微量元素含量时, 应根据待检测元素类型特征, 选择适宜的检测仪器。