School of Chemical Engineering, Universiti Sains Malaysia, 14300, Nibong Tebal, Pulau Pinang, Malaysia.
Centre of Chemical Engineering, College of Engineering, Universiti Teknologi MARA, Cawangan Pulau Pinang, 13500, Permatang Pauh, Pulau Pinang, Malaysia.
Environ Sci Pollut Res Int. 2023 Feb;30(7):17129-17148. doi: 10.1007/s11356-022-20627-x. Epub 2022 May 12.
Removal of HS (hydrogen sulfide) from biogas is anticipated for higher energy conversion of methane (CH), while reducing the detrimental impacts of corroding the metal parts in the plant and its hazardous effect on humans and the environment. The introduction of microwave (MW) heating and nitrogen-modification could generate superior adsorbent features, contributing to high HS removal. Up to date, there is no work reported on the influence of physicochemical characteristics of nitrogen-modified carbon synthesized via MW and conventional heating (TH) methods and their performance in HS removal. Palm shell activated carbon (PSAC) was functionalized with nitrogen groups via urea impregnation, followed by the synthesis of MW and TH at 950 °C, 500 ml/min of N flow rate and 30 min of heating time. MW and TH heating effects on the modified PSAC adsorbent were analysed and compared towards hydrogen sulfide (HS) removal. PSAC with nitrogen functionalization produced using MW heating (PSAC-MW) demonstrates superior performance, with an adsorption capacity of 356.94 mg/g. The adsorbent sample generated using MW heating exhibited notable properties, including a large surface area and a sponge-like structure, with new pores developed within the current pores. Instead of that, there was an observation of 'hot spot' appearance during the MW heating process, which is believed to be responsible for the development of physical and chemical characteristics of the adsorbent. Thus, it is believed that MW heating was assisted in the development of the adsorbent's properties and at the same time contributed to the high removal of HS at low adsorption temperature. The utilization of biomass-based adsorbent (PSAC) for HS removal can address the lignocellulosic waste disposal problem, while mitigating the HS release from the biogas production plants thus has several environmental merits. This indirectly contributed to zero-waste generation, while overcoming the adverse effects of HS.
从沼气中去除 HS（硫化氢）有望提高甲烷 (CH) 的能量转化率，同时减少对工厂金属部件的腐蚀和对人类及环境的有害影响。微波 (MW) 加热和氮改性的引入可以产生更好的吸附剂特性，有助于实现高 HS 去除率。迄今为止，尚未有报道研究通过 MW 和常规加热 (TH) 方法合成的氮改性碳的物理化学特性及其在 HS 去除方面的性能。通过尿素浸渍对椰壳活性炭 (PSAC) 进行氮功能化，然后在 950°C、500ml/min 的 N 流速和 30 分钟的加热时间下分别通过 MW 和 TH 进行合成。分析和比较了 MW 和 TH 加热对改性 PSAC 吸附剂去除硫化氢 (HS) 的影响。使用 MW 加热制备的氮功能化 PSAC（PSAC-MW）表现出优异的性能，吸附容量为 356.94mg/g。MW 加热生成的吸附剂样品表现出显著的性质，包括较大的表面积和海绵状结构，当前孔内开发了新的孔。然而，在 MW 加热过程中观察到“热点”的出现，据信这是导致吸附剂物理化学特性发展的原因。因此，人们认为 MW 加热有助于发展吸附剂的性能，同时有助于在低吸附温度下实现 HS 的高效去除。利用基于生物质的吸附剂（PSAC）去除 HS 可以解决木质纤维素废物处理问题，同时减少沼气生产厂释放的 HS，因此具有多项环境优势。这间接有助于实现零废物生成，同时克服 HS 的不利影响。
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