Department of Renewable Energy Engineering, Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, 641003, India.
Department of Renewable Energy Engineering, Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, 641003, India.
Environ Res. 2022 Nov;214(Pt 3):114022. doi: 10.1016/j.envres.2022.114022. Epub 2022 Aug 14.
Adsorption is the most promising technology used in the gas separation and purification process. The key success of this technology relies on the selection of an adsorbent. Activated carbon and zeolites are the most commonly used adsorbents in the separation of particular gas from gaseous mixtures. Activated carbon deriving from fossil and biomass-based resources has wide pore size distribution and thereby results in lower selectivity. Whereas, zeolites synthesized from natural minerals are expensive which increases the cost of the purification process. Taking this into concern, the quest for synthesizing low-cost and effective adsorbents has gained greater attention in recent years. Carbon Molecular Sieves (CMSs), are considered as an attractive alternative to replace the conventional adsorbents. Furthermore, CMSs exhibit higher selectivity and adsorption capacity, due to their narrow micropore size distribution (0.3-0.5 nm). CMSs are synthesized from any organic carbonaceous precursor with low inorganic content. Since most of the agricultural residues fall under this category, they can be used as a feedstock for CMSs production. The synthesis of CMSs involves three stages: carbonization, activation, and pore modification. In this review, physicochemical characteristics of various agricultural residues, the effects of carbonization process parameters, activation methods, and pore modification techniques adopted for producing CMSs are comprehensively discussed. The effect of deposition temperature, time, and flow rate of depositing agent on pore characteristics of CMSs is briefed. The prospects and challenges in CMSs production are also studied. The insights in this review provide guidelines for synthesizing CMSs from agro-residues.
吸附是气体分离和净化过程中最有前途的技术。该技术的关键成功依赖于吸附剂的选择。活性炭和沸石是从气体混合物中分离特定气体最常用的吸附剂。源自化石和生物质资源的活性炭具有较宽的孔径分布，因此选择性较低。而天然矿物质合成的沸石则价格昂贵，增加了净化过程的成本。考虑到这一点，近年来人们越来越关注合成低成本、高效的吸附剂。碳分子筛（CMSs）被认为是替代传统吸附剂的一种有吸引力的选择。此外，由于其窄的微孔尺寸分布（0.3-0.5nm），CMSs 表现出更高的选择性和吸附能力。CMSs 可由任何低无机含量的有机碳质前体制成。由于大多数农业废弃物都属于这一类，因此它们可以用作 CMSs 生产的原料。CMSs 的合成包括三个阶段：碳化、活化和孔改性。在这篇综述中，全面讨论了各种农业废弃物的物理化学特性、碳化过程参数、活化方法和孔改性技术对 CMSs 生产的影响。简要介绍了沉积温度、沉积时间和沉积剂流速对 CMSs 孔特性的影响。还研究了 CMSs 生产的前景和挑战。本综述中的见解为从农业废料中合成 CMSs 提供了指导。
