Method for preparing efficient heavy metal adsorbent from modified cotton stalk biomass charcoal

Abstract

The invention discloses a method for preparing a high-efficiency heavy metal adsorbent by modifying cotton stalk biomass charcoal. Carbonization at 300°C for 3‑6h; (2) Add 0.3mol / L KMnO to the cotton biochar prepared in step (1) 4 solution, and then add a mass fraction of 60% HNO 3 solution, heated at 85-95°C for 2.5-3.5h, filtered, washed, and dried to obtain a modified product, the biochar and KMnO 4 solution and HNO 3 The dosage ratio of the solution is 1g: (7-7.8)ml: (3.3-4.0)ml. The pore volume of the biomass charcoal obtained by carbonizing the cotton stalks prepared by the method of the invention is obviously increased, and can efficiently adsorb heavy metal copper and cadmium at the same time.

Description

technical field [0001] The invention relates to a method for preparing a heavy metal high-efficiency adsorbent by modifying cotton straw biomass charcoal. Background technique [0002] Biochar refers to a carbon-rich product obtained from biomass (such as straw, wood, manure, leaves, etc.) in an anoxic and low-oxygen closed environment. The performance of biochar mainly depends on the physical and chemical properties of biochar, and biochar prepared from different raw materials has different properties. For example, the nutrient content of biochar prepared from animal feces is higher than that of biochar prepared from plant straws (Liu Yingying. The basic properties of biochar from different raw materials and their effects on Cd~(2+) and Pb~(2+ ) Research on adsorption characteristics [D]. Nanjing Agricultural University, 2012). The physical and chemical properties of biochar prepared from the same biomass material at different carbonization temperatures and parameters are...

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Problems solved by technology

The advantage of the zinc chloride activation method is that the operation is relatively simple, but because the zinc chloride is difficult to recycle, and the volatilized hydrogen chloride and zinc chloride pollute the environment and endanger human health; H 3 PO 4 The activation method has the advantages of little environmental pollution and low cost, but because the process is prepared under high temperature conditions, the product has a small pore size and low performance; the activated carbon prepared by the KOH activation method has a large specific surface area, Uniform pores and strong adsorption capacity, but KOH is easy to corrode equipment, pollute the environment, and increase costs

[0005] Chinese patent 201310018252.2 discloses a preparation method of nano black carbon passivator, which discloses the use of potassium permanganate and nitric acid as oxidants for passivation, but it is necessary to mix potassium permanganate and nitric acid and then add it to black carbon for a long time. Pre-oxidation for 24 hours, followed by heating and oxidation for 3 hours, the steps are cumbersome and the reaction time is long, which is not conducive to large-scale industrial production

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