Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China.
Int J Environ Res Public Health. 2022 Jul 23;19(15):8953. doi: 10.3390/ijerph19158953.
The pyrolysis characteristics of cadmium (Cd)-impregnated cellulose, hemicellulose, and lignin were studied to elucidate the pyrolysis velocity and deoxygenation characteristics of Cd-contaminated rice straw. The results show that Cd significantly affects the pyrolysis characteristics of a single biomass component. With a heating rate of 5 °C·min and a Cd loading of 5%, the initial pyrolysis temperature of cellulose and hemicellulose decreases while that of lignin increases. The maximum pyrolysis velocity of cellulose, hemicellulose, and lignin is decreased by 36.6%, 12.4%, and 15.2%, respectively. Cd increases the pyrolysis activation energy of the three components and inhibits their deoxygenation. For the pyrolysis of Cd-contaminated rice straw, both the initial depolymerization temperature and the pyrolysis velocity of hemicellulose is reduced, while the pyrolysis velocity of cellulose is accordingly increased. When Cd loading amplifies to 0.1%, 1%, and 5%, the maximum pyrolysis velocity of hemicellulose is decreased by 7.2%, 10.5%, and 21.3%, while that of cellulose is increased by 8.4%, 62.1%, and 97.3%, respectively. Cd reduces the release of volatiles and gas from rice straw, such as CO, CO, and oxygen-containing organics, which retains more oxygen and components in the solid fraction. This research suggested that Cd retards the pyrolysis velocity and deoxygenation of rice straw, being therefore beneficial to obtaining more biochar.
研究了镉（Cd）浸渍纤维素、半纤维素和木质素的热解特性，以阐明Cd 污染稻草的热解速度和脱氧特性。结果表明，Cd 显著影响单一生物质成分的热解特性。在 5°C·min 的加热速率和 5%的 Cd 负载下，纤维素和半纤维素的初始热解温度降低，而木质素的初始热解温度升高。纤维素、半纤维素和木质素的最大热解速度分别降低了 36.6%、12.4%和 15.2%。Cd 增加了三种成分的热解活化能并抑制了它们的脱氧。对于 Cd 污染稻草的热解，半纤维素的初始解聚温度和热解速度降低，而纤维素的热解速度相应增加。当 Cd 负载增加到 0.1%、1%和 5%时，半纤维素的最大热解速度分别降低了 7.2%、10.5%和 21.3%，而纤维素的热解速度分别增加了 8.4%、62.1%和 97.3%。Cd 减少了稻草中挥发性物质和气体的释放，如 CO、CO 和含氧有机物，从而保留了更多的氧和固体部分的成分。这项研究表明，Cd 会减缓稻草的热解速度和脱氧，因此有利于获得更多的生物炭。
