This research article deals with the synthesis of a heterogeneous eggshell-coconut pith catalyst for the transesterification of preutilized cooking oil into a biodiesel fuel. A wet impregnation technique was adopted to prepare the heterogenous catalyst from calcined eggshells and activated coconut pith, followed by the surface analysis for pores using the scanning electron microscopy. The synthesized catalyst was employed for the transesterification of preutilized or waste cooking oil for its conversion into fatty acid methyl esters. Response surface methodology (RSM) using a four factor, three level, central composite design (CCD) was used to investigate the effect of the process parameters (alcohol:oil ratio [4:1,6:1,8:1], temperature [30°C, 50°C, and 70°C], time [60, 120, and 180 min], and ESCP-catalyst dosage [1, 5, and 9 wt.%]) on the response variable, biodiesel yield. The biodiesel yield from preutilized cooking oil was found to be 72% at the optimized process conditions (50°C, 8:1 methanol to oil molar ratio, 5 wt.% ESCP-catalyst, reaction time of 60 min). The GC-MS analysis of biodiesel produced showed peaks relevant to conventional diesel. The study has resulted in the synthesis of a stable, cost effective, highly active catalyst for the preutilized cooking oil transesterification into biodiesel.

中文翻译：

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使用可再生的非均相蛋壳-椰子髓催化剂从预先利用的食用油生产生物柴油：工艺优化和表征

这篇研究文章涉及多相蛋壳-椰子髓催化剂的合成，用于将预先利用的食用油酯交换为生物柴油燃料。采用湿法浸渍技术从煅烧蛋壳和活化椰子髓中制备多相催化剂，然后使用扫描电子显微镜对孔隙进行表面分析。合成的催化剂用于预先利用或废弃食用油的酯交换，以将其转化为脂肪酸甲酯。响应面法 (RSM) 使用四因素、三水平、中心复合设计 (CCD) 来研究工艺参数（醇油比 [4:1,6:1,8:1]、温度[30°C、50°C 和 70°C]、时间 [60、120 和 180 分钟]，以及 ESCP 催化剂剂量 [1、5 和 9 wt. %]) 响应变量，生物柴油产量。发现在优化的工艺条件下（50°C，8:1 甲醇与油摩尔比，5 wt.% ESCP 催化剂，反应时间为 60 分钟），来自预利用食用油的生物柴油产率为 72%。生产的生物柴油的 GC-MS 分析显示出与传统柴油相关的峰。该研究合成了一种稳定、成本效益高、活性高的催化剂，用于将预先利用的食用油酯交换成生物柴油。