Nano magnesium oxide loaded biochar composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of adsorption materials, and discloses a nano magnesium oxide loaded biochar composite material as well as a preparation method and application thereof. The preparation method comprises the following steps of: soaking a biochar material in a nano magnesium hydroxide impregnation liquid prepared by mixing ammonia water and a magnesium chloride solution, and then performing high-temperature decomposition to form the nano magnesium oxide loaded biochar composite material in which nano magnesium oxide can be uniformly distributed. The nano magnesium oxide particles of the nano magnesium oxide loaded biochar composite material prepared by the invention are uniformly distributed, and the nano magnesium oxide loaded biochar composite material has a good adsorption effect on heavy metals such as Pb (II), Cd (II), Cr (VI) and Sb (III), and has good potential of repairing heavy metal pollution of water. The preparation process is simple and easy to implement, and the preparation cost is low. Waste agricultural and forestry biomass is fully utilized, ammonia water and magnesium chloride in the modification process do not cause secondary pollution to the environment, and environmental pollution and carbon emission of waste biomass are reduced. The composite material can be applied to heavy metal pollution remediation, and lead, cadmium, antimony, chromium and the like in an aqueous solution can be efficiently removed.

Description

technical field [0001] The invention belongs to the technical field of adsorption materials, and in particular relates to a biochar composite material loaded with nano-magnesia and its preparation method and application. Background technique [0002] Biochar is a carbon-rich solid product formed by pyrolysis of waste biomass materials under anoxic conditions. It can adsorb and remove heavy metals in water or immobilize and passivate heavy metals in soil to reduce their toxicity. Biochar has strong resistance to decomposition in the natural environment. Using biochar-based materials to remove heavy metals in polluted water or passivate heavy metals in soil can effectively reduce the pollution of heavy metals in the environment and help to fix a large amount of carbon in waste biomass. However, due to Unmodified biochar has limited adsorption capacity for heavy metals, and further modification is needed to improve the surface characteristics, functional group structure and ads...

AI Technical Summary

Problems solved by technology

The ultrasonic impregnation method and nano-magnesium hydroxide decomposition method used in the prior art are more commonly used nano-magnesia loading methods, but when the ultrasonic impregnation method is used, excessive magnesium chloride crystal particles will produce larger aggregations during the heating reaction process. body, resulting in uneven distribution of nano-magnesium oxide on biochar, and even blocking the pores of biochar; when nano-magnesium hydroxide decomposition method is used, excessive nano-magnesium hydroxide is easy to aggregate, and it is loaded on biochar and treated at high temperature. Magnesium hydroxide is difficult to fully decompose to form nano-magnesia. At this time, the preparation efficiency of biochar composites loaded with nano-magnesia is not high, and the controllability is not strong.

The biochar composites loaded with nano-magnesia prepared by these methods have low adsorption efficiency for heavy metals, and the improvement of heavy metal removal efficiency is very limited, which cannot meet the existing needs.

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