In this study, biodiesel was produced from waste coffee grounds (WCGs) using solid catalysts manufactured from waste eggshells (WESs). A one-step direct process (OSDP), comprising extraction of lipids from WCGs and simultaneous transesterification of these lipids with methanol in a reactor, was employed. To facilitate reuse of the solid catalysts, a cartridge containing the solid catalysts was devised and applied in the OSDP. The optimal reaction conditions of the OSDP with the cartridge were 100 wt% catalyst relative to WCGs, the mixture of 4.0 mL methanol and 4.0 mL n-hexane per gram WCG, 45°C, 9 h, and 200 rpm. Under these optimal conditions, an 8.7% biodiesel yield (g-biodiesel/g-WCGs) was achieved. Solid catalysts retained in the cartridge were successfully reused for seven rounds of repeated batch operation and, using this approach, a biodiesel yield exceeding 92% of that of the first batch operation was maintained.

在这项研究中，使用废鸡蛋壳（WES）制成的固体催化剂从废咖啡渣（WCG）生产生物柴油。采用了一步直接法（OSDP），包括从WCG中提取脂质并在反应器中同时将这些脂质与甲醇进行酯交换反应。为了促进固体催化剂的再利用，设计了包含固体催化剂的药筒，并将其应用在OSDP中。OSDP的最佳反应条件是，相对于WCG，催化剂的最佳反应条件为100 wt％，每克WCG为4.0 mL甲醇和4.0 mL正己烷的混合物，温度为45°C，9 h和200 rpm。在这些最佳条件下，实现了8.7％的生物柴油收率（g-biodiesel / g-WCGs）。保留在滤芯中的固体催化剂已成功重复使用了七轮重复的分批操作，并且使用这种方法，