Insight into the catalytic properties zeolitized kaolinite/diatomite geopolymer as an environmental catalyst for the sustainable conversion of spent cooking oil into biodiesel; optimization and kinetics

Inorganic zeolite/geopolymer composite (Z/GP) was synthesized by controlled zeolitization of synthetic geopolymer from kaolinite and diatomite to be used as a potential catalyst in the transesterification of commercial spent cooking oil (SCO). The Z/GP composite demonstrates promising microstructural properties (106 m²/g surface area and 4.2 nm average pore diameter) and chemical structural enrich in OH and Na⁺ ions as active basic and catalytic centers. The Z/GP composite as catalyst was applied in the transesterification of SCO according to suggested experiment conditions from statistical design which was built based on the Response Surface Methodology. The measured biodiesel yield from SCO over Z/GP catalyst is 98.1% at experimental conditions of 40 °C as temperature, 90 min as time, 12:1 as methanol/SCO ratio, and 3.25 wt, % as Z/GP loading value. The theoretical optimization function of the statistical design suggested potential enhancement for the performance of the reaction to achieve a yield of 99% by adjusting the values of the studied factors at 54.9 °C, 81.9 min, at 12:1, and 3.48 wt, % for the temperature, time, methanol/SCO ratio, and Z/GP loading. The physical properties of the produced SCO-based biodiesel over Z/GP demonstrate the suitability of the product to be used as biofuels considering the criteria to international standards. The kinetic properties of the transesterification reactions of SCO over Z/GP catalyst follow the Pseudo-First order kinetic assumption and occurred with low activation energy. Finally, the synthetic Z/GP as a solid basic catalyst is of significant reusability and reused five times with remarkable biodiesel yields.     

中药赤石脂的红外光谱分析

目的研究中药赤石脂的红外光谱特征。方法用红外光谱法(IR)对不同来源的矿物药赤石脂进行测定,研究赤石脂的红外光谱特征。结果对不同产地的29批次赤石脂样本进行红外光谱分析,不同来源的赤石脂在3 618cm-1及3 695 cm-1波数处存在差异,可以有效区分赤石脂及高岭石。结论运用傅立叶变换红外光谱技术可以对不同来源的赤石脂及高岭石进行直接、快速、准确分析,为此类矿物药的鉴别和质量控制提供可靠的依据。     

Ionic liquids in soils: effects of different anion species of imidazolium based ionic liquids on wheat (Triticum aestivum) as affected by different clay minerals and clay concentrations

This study contributes to a prospective hazard assessment of ionic liquids, focusing on the terrestrial environment. The influence of differently composed soils—varying contents of the clay minerals smectite and kaolinite—on the toxicity of different anion species of imidazolium based ionic liquids was studied for growth inhibition of wheat (Triticum aestivum). IM14 (CF₃SO₂)₂N appeared the most toxic, independently of the investigated soil type. The toxicity of IM14 Cl, IM14 BF₄ and IM14 HSO₄ was mainly dominated by the cationic moiety. The observed effects varied in dependence of the added clay type and clay concentration. An increase of clay content resulted in less pronounced effects of these substances. In contrast, for IM14 (CF₃SO₂)₂N the addition of clay minerals caused higher toxic effects in comparison to the reference soil. Our results give first hints for the assumption, that ionic liquids whose toxic action is based on the anionic moiety are especially hazardous for soils, particular for soils with high clay contents.