Effective synthesis of ethylene urea from CO_2 adsorbed cerium doped Mg–Al layered double hydroxide

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作   者：

Farzana Rahman;  Xinyi Yang;  Fiona Motswaiso;  Itsuki Takanashi;  Tomohito Kameda;  Mir Tamzid Rahman;  Yuko Saito;  Shogo Kumagai;  Toshiaki Yoshioka; 

作者机构：

Sendai 980-8579;  Tohoku University;  Daffodil International University;  Japan||Department of Chemistry;  Jahangirnagar University;  Japan;  Bangladesh;  Japan||Department of General Educational Development;  Graduate School of Environmental Studies;  Birulia 1216;  Dhaka 1342; 

关键词：

Ce-doped Mg–Al LDH;  Promoter;  CO_2 adsorption;  Ethylene urea; 

期刊名称：

Journal of cleaner production

i s s n：

0959-6526

年卷期：

2024 年 434 卷 Jan.1 期

页   码：

140191.1-140191.9

页   码：

摘   要：

The steady increase in CO_2 levels in the atmosphere is the leading cause of climate change and global warmingand is now a global concern. To reduce the impact of CO_2, various novel routes have been proposed to capture,utilize, and convert it into valuable chemicals. In this study, a noble Ce-doped Mg–Al layered double hydroxide(Mg–Al LDH) [Mg/Al molar ratio = 3 and Ce/Al molar ratio = 0.1, 0.5, 1.0] were synthesized using coprecipitationand sol–gel method and used as an adsorbent for CO_2 gas and later on efficient source of CO_2 inthe synthesis of ethylene urea (EU). The specific surface area of the Ce-doped Mg–Al LDHs prepared by sol-gelmethod (96.1–333 m~2/g) were higher than co-precipitation method (0.5–10.6 m~2/g). Each Ce-doped Mg–AlLDHs were successfully adsorbed CO_2, where first desorption occurred at around 50–250 ℃ temperature. Thecomparative adsorption of CO_2 was observed increase with decreasing the Ce/Al molar ratio. Adsorption of CO_2was found to be 0.05, 0.04, 0.04 mmol/g for co-precipitation method and 0.62, 0.42, 0.37 mmol/g for sol-gelmethod, where Ce/Al molar ratio was 0.1, 0.5, 1.0 respectively. The EU produced from the reaction betweenethylenediamine (EDA) and CO_2 adsorbed Ce-doped Mg–Al LDHs, where a comparative amount of EU wasobserved in the order of Ce/Al molar ratio = 1.0 > 0.5 > 0.1. According to the temperature effect, EU productionwas increased with an increase in temperature from 120 ℃ to 160 ℃. At 160 ℃, the production of EU by coprecipitationmethod was found to be 0.03, 0.04, 0.07 mmol/g and by sol-gel method was found to be 0.06,0.07, 0.16 mmol/g, where Ce/Al molar ratio was 0.1, 0.5, 1.0 respectively. A much higher production was foundin all the Ce-doped Mg–Al LDHs compared to pristine Mg–Al LDH at all the temperatures. The performance of CedopedMg–Al LDHs synthesized by the sol-gel method was observed to be better than that of the co-precipitationmethod in terms of both adsorption of CO_2 and production of EU. In this study, Ce-doped Mg–Al LDH introducedas a successful CO_2 adsorbent, a source of CO_2 and an effective promoter in the ethylene urea production.