Department of Soil and Water Sciences, College of Resources and Environment, China Agricultural University, Beijing 100193, China.
Department of Soil and Water Sciences, College of Resources and Environment, China Agricultural University, Beijing 100193, China; Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture/Key Laboratory of Plant-Soil Interactions, Ministry of Education, Beijing 100193, China.
Sci Total Environ. 2020 Apr 20;714:136532. doi: 10.1016/j.scitotenv.2020.136532. Epub 2020 Jan 7.
The development of distinct biochar from agricultural waste for soil and environment remediation is valuable. Moderate pretreatment with sodium hydroxide may open the lignocellulosic structure of crop straw and then enhance the impregnation of iron oxides and phosphates, finally leading to the production of distinct biochars. In this study, two common agricultural wastes of rice and cotton straw were first treated with a dilute NaOH solution and then soaked in either Fe-Co nitrate or HPO solution. The biochars produced through a slow pyrolysis process were then analyzed with respect to their physico-chemical and adsorptive properties. The results showed that all pretreatments remarkably changed the physico-chemical properties of the feedstocks and subsequently endowed the biochars with distinct characteristics. The biochars had specific surface areas (SSAs) ranging from 12.26 to 581.13 m/g, total pore volumes (TPVs) ranging from 0.033 to 0.3736 cm/g and average pore volumes (APSs) ranging from 2.57 to 10.76 nm. They also contained a large amount of positive charge, an anion exchange capacity (pH 3.5) ranging from 251.78 to 810.13 mmol/kg, and a certain amount of negative charge as well, cation exchange capacity (pH 7.0) ranging from 108.22 to 464.67 mmol/kg. The adsorption capacities of the modified biochars toward both Pb and Cd were 23.07-82.74% and 16.90-556.33% higher than those of pristine biochars, respectively. Of the modified biochars, the Fe-Co-composite biochar showed many promising physico-chemical and adsorptive properties for adsorbing divalent metals of both Pb and Cd and might thus have high potential as a soil amendment and an alternative adsorbent for environmental remediation.
从农业废弃物中开发独特的生物炭用于土壤和环境修复是有价值的。用氢氧化钠适度预处理可以打开农作物秸秆的木质纤维素结构，然后增强氧化铁和磷酸盐的浸渍，最终导致独特生物炭的产生。在这项研究中，首先用稀氢氧化钠溶液处理两种常见的农业废弃物——水稻和棉花秸秆，然后将它们浸泡在硝酸铁-钴或磷酸溶液中。然后通过慢速热解过程分析所产生的生物炭的物理化学和吸附性能。结果表明，所有预处理都显著改变了原料的物理化学性质，并随后赋予生物炭独特的特性。生物炭的比表面积（SSA）范围为 12.26 至 581.13 m/g，总孔体积（TPV）范围为 0.033 至 0.3736 cm/g，平均孔径（APS）范围为 2.57 至 10.76 nm。它们还含有大量正电荷，pH 值为 3.5 时的阴离子交换容量（AE）范围为 251.78 至 810.13 mmol/kg，以及一定量的负电荷，pH 值为 7.0 时的阳离子交换容量（CE）范围为 108.22 至 464.67 mmol/kg。改性生物炭对 Pb 和 Cd 的吸附容量分别比原始生物炭高 23.07%至 82.74%和 16.90%至 556.33%。在改性生物炭中，Fe-Co 复合生物炭对 Pb 和 Cd 两种二价金属具有许多有前途的物理化学和吸附性能，因此可能具有作为土壤改良剂和环境修复替代吸附剂的高潜力。
