Arabyarmohammadi Hoda, Darban Ahmad Khodadadi, Abdollahy Mahmoud, Ayati Bita
1Mineral Processing Group, Mining Engineering Department, Tarbiat Modares University, Tehran, Iran.
2Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran.
J Environ Health Sci Eng. 2018 Jul 24;16(2):109-119. doi: 10.1007/s40201-018-0294-6. eCollection 2018 Dec.
Biochars are the new generation of sustainable soil amendments which may be applied both to fertilize and remediate the impacted soils. The aim of current research has been synthesis and characterization of pulp and paper-derived biochars and determination of their mechanisms in simultaneous immobilization of heavy metals (Cu, Pb, and Zn) within contaminated soil. In a novel attempt, three different solid wastes of Mazandaran Wood and Paper Industries (barks and effluent sludge) were utilized to produce biochars.
The thermogravimetric behavior of the three selected biomasses were initially analyzed and the proper pyrolysis condition has been determined, accordingly. Alterations in surface active groups, before and after the pyrolysis process, have been detected by Fourier transform infrared (FTIR) spectroscopy. Elemental analysis and acid digestion procedure have been employed to measure C, H, N, S, O, and P contents of the biochars. Moreover, porosity and morphological characteristics have been monitored by Brauner-Emmet-Teller (BET) porosimetry and scanning electron microscopy (SEM). Batch adsorption tests have been designed and carried out. Finally, a set of soil sequential extraction experiments was performed over both amended/unamended soils which together with a post-sorption FTIR analysis, explained the possible competitive immobilization mechanism.
Porosimetry study indicated the nanoporosity of the chars and the distribution pattern of adsorbed metals over the char samples. Batch sorption tests suggested remarkable uptake capacity for each char. The results of post sorption tests suggested that Cu is mainly involved in organic bonds of -NH2, -OH and -COOH groups, Pb forms insoluble hydroxide, phosphate or carbonate precipitates, and Zn is mostly engaged in the residual fraction.
Accordingly, the bulky wastes are confirmed to have the potential to form sustainable biochar soil amendments.
生物炭是新一代可持续土壤改良剂，可用于施肥和修复受污染土壤。当前研究的目的是合成和表征纸浆和造纸衍生生物炭，并确定其在污染土壤中同时固定重金属（铜、铅和锌）的机制。在一项新的尝试中，利用马赞德兰木材和造纸工业的三种不同固体废物（树皮和废水污泥）来生产生物炭。
首先分析了三种选定生物质的热重行为，并据此确定了合适的热解条件。通过傅里叶变换红外（FTIR）光谱检测热解过程前后表面活性基团的变化。采用元素分析和酸消解程序测量生物炭的碳、氢、氮、硫、氧和磷含量。此外，通过布鲁诺尔-埃米特-泰勒（BET）孔隙率测定法和扫描电子显微镜（SEM）监测孔隙率和形态特征。设计并进行了批量吸附试验。最后，对改良/未改良土壤进行了一系列土壤连续提取实验，并结合吸附后FTIR分析，解释了可能的竞争固定机制。
孔隙率研究表明了生物炭的纳米孔隙率以及吸附金属在炭样品上的分布模式。批量吸附试验表明每种生物炭都具有显著的吸附能力。吸附后试验结果表明，铜主要参与-NH2、-OH和-COOH基团的有机键合，铅形成不溶性氢氧化物、磷酸盐或碳酸盐沉淀，锌主要存在于残留部分。
因此，证实这些大量废物有潜力形成可持续的生物炭土壤改良剂。
