Komariah Leily Nurul, Arita Susila, Cundari Lia, Afrah Bazlina Dawami
Department of Chemical Engineering, Faculty of Engineering, Universitas Sriwijaya 30662 Indralaya Ogan Ilir Indonesia
RSC Adv. 2024 Feb 19;14(9):6112-6120. doi: 10.1039/d3ra08264d. eCollection 2024 Feb 14.
Crude glycerol (CG) is a major byproduct of biodiesel production. Most of it cannot be utilized due to major impurities. The CG generally contains alkalis, which generate the residual salts in a series of its purification stages. This study aims to obtain the optimum process conditions and acid molar ratio to produce a higher potassium salt yield while improving the purity of glycerol by a simple acidification procedure. The CG was obtained from the transesterification of palm oil using a catalyst based on potassium carbonate. A phosphoric acid (85%) is utilized at various molar ratios and the process temperature is 60-80 °C. The strong acid was slowly added to the CG and heated for 30 minutes with a mixing speed of 250 rpm. The optimum acidification process occurred at a temperature of 70 °C with a molar crude glycerol ratio to phosphoric acid of 1 : 0.5. The glycerol purity was increased from 43.3% to 67.63% (w/w). It effectively obtains a potassium phosphate salt with a yield of 6.78%. The functional group infrared (IR) and X-ray fluorescence (XRF) spectra identified the salt residue as potassium dihydrogen phosphate (KHPO). This is composed predominantly of potassium oxide (KO) and phosphorus pentoxide (PO), 50% and 47.9%, respectively.
粗甘油（CG）是生物柴油生产的主要副产物。由于含有大量杂质，其大部分无法得到利用。粗甘油通常含有碱，在其一系列提纯阶段会产生残留盐。本研究旨在通过简单的酸化程序获得最佳工艺条件和酸摩尔比，以提高钾盐产率，同时提高甘油纯度。粗甘油是由棕榈油使用碳酸钾基催化剂进行酯交换反应制得。使用不同摩尔比的磷酸（85%），工艺温度为60 - 80℃。将强酸缓慢加入到粗甘油中，并以250转/分钟的混合速度加热30分钟。最佳酸化过程发生在70℃，粗甘油与磷酸的摩尔比为1∶0.5时。甘油纯度从43.3%提高到了67.63%（w/w）。有效获得了产率为6.78%的磷酸钾盐。官能团红外（IR）光谱和X射线荧光（XRF）光谱鉴定该盐残余物为磷酸二氢钾（KHPO）。它主要由氧化钾（KO）和五氧化二磷（PO）组成，分别占50%和47.9%。
