Abstract

Spent biochar obtained after water treatment especially metal adsorption could be used as a solid fuel. In this study, soil application potential and fuel value of cadmium contaminated biochar was investigated. Biochar prepared from Parthenium (PBC) and the thermally modified biochar (MPBC) was artificially contaminated with different concentrations (1, 10, 50, 100 and 200 mg/l) of Cd solution. The contaminated PBC-Cd and MPBC-Cd was applied to a red soil, and their impact on soil biological activity, maize growth and Cd bioaccumulation was assessed. Maize growth was retarded due to the contaminated biochar. Soil and plant Cd concentrations increased significantly. The soil dehydrogenase (DHA) and fluorescein diacetate hydrolases enzyme activities were adversely affected. DHA reduced from 324 to 97 mg TPF/kg/24 h in MPBC-1 to MPBC-200, while in PBC-1 to PBC-200, DHA decreased from 422 to 112 mg TPF/kg/24 h. Cd contaminated biochars obtained after waste water treatment could not be used for soil application. Fuel values of contaminated biochar were analysed by the higher heating value of biochars and their fusibility indices. The high heating value of the biochar is comparable with the lignite. Raw biochar contains significant amount of alkali elements that affected their use as a fuel. However after adsorption, the washing of the biochar alkalies significantly improved the fuel properties, especially the propensity for slagging and fouling. Biochar used for treatment of contaminated waste water could be sustainably used as a solid fuel; however further studies are needed to manage the metal enriched ash generated after combustion of these contaminated biochar.

中文翻译：

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水处理后获得的镉污染生物炭的燃料价值和土壤利用潜力的评估

摘要

经过水处理，尤其是金属吸附后获得的废生物炭可用作固体燃料。在这项研究中，研究了镉污染的生物炭在土壤中的应用潜力和燃料价值。由Parthenium制备的生物炭（PBC）和热改性生物炭（MPBC）被不同浓度（1、10、50、100和200 mg / l）的Cd溶液人工污染。将受污染的PBC-Cd和MPBC-Cd应用于红壤，并评估它们对土壤生物活性，玉米生长和Cd生物积累的影响。由于生物炭的污染，玉米的生长受阻。土壤和植物中的镉浓度显着增加。土壤脱氢酶（DHA）和荧光素二乙酸酯水解酶活性受到不利影响。在MPBC-1至MPBC-200中，DHA从324降低到97 mg TPF / kg / 24 h，而在PBC-1至PBC-200中，DHA从422降低到112 mg TPF / kg / 24 h。废水处理后获得的镉污染的生物炭不能用于土壤。通过较高的生物炭热值及其可熔性指数分析受污染的生物炭的燃料值。生物炭的高发热量可与褐煤媲美。原始生物炭含有大量的碱金属元素，影响了其用作燃料的用途。然而，在吸附之后，生物炭碱的洗涤显着改善了燃料性能，特别是结渣和结垢的倾向。用于处理受污染废水的生物炭可以可持续地用作固体燃料；但是，需要进一步研究来管理这些受污染的生物炭燃烧后产生的金属富集灰分。原始生物炭含有大量的碱金属元素，影响了其用作燃料的用途。然而，在吸附之后，生物炭碱的洗涤显着改善了燃料性能，特别是结渣和结垢的倾向。用于处理受污染废水的生物炭可以可持续地用作固体燃料；但是，需要进一步研究来管理这些受污染的生物炭燃烧后产生的金属富集灰分。原始生物炭含有大量的碱金属元素，影响了其用作燃料的用途。然而，在吸附之后，生物炭碱的洗涤显着改善了燃料性能，特别是结渣和结垢的倾向。用于处理受污染废水的生物炭可以可持续地用作固体燃料；但是，需要进一步研究来管理这些受污染的生物炭燃烧后产生的金属富集灰分。