Method for preparing silver-loaded activated charcoal through low-temperature reduction and pyrolysis of urea

Abstract

The invention relates to a method for preparing silver-loaded activated charcoal through low-temperature reduction and pyrolysis of urea. The silver-loaded activated charcoal is prepared through preparing a silver nitrate and urea complexing solution, carrying out activated charcoal infiltration and carrying out pyrolysis and reduction. The method comprises the steps: firstly preparing the silver nitrate-urea complexing solution, of which the mole ratio of silver nitrate to urea is (1 to 0.625): 1 and the mass concentration of Ag ions is 0.01% to 0.6%; carrying out soaking for 6 to 24 hours in accordance with that the ratio of activated charcoal to the complexing solution is 0.25Kg / L to 1Kg / L; carrying out pyrolysis under circulating nitrogen protection; and carrying out washing with clean water, and then, carrying out drying, thereby obtaining the silver-loaded activated charcoal. The particle size of nano-silver is 10nm to 60nm; the loaded silver amount is 0.01wt.% to 0.4wt.%; the binding power between silver particles and the activated charcoal is high, and the rate of loss of silver is not higher than 30% under the conditions of 150r / min and 600 hours of oscillation in constant-temperature water with the temperature of 25 DEG C; and the dispersity of the silver particles is good, process flows are shortened, the reaction temperature is lowered, the fungicidal efficiency of the silver-loaded activated charcoal is increased, and the consumption of silver is lowered.

Description

technical field [0001] The invention relates to a method for carrying silver activated carbon. It uses silver nitrate and urea complex solution, then impregnates activated carbon, and after thermal decomposition and reduction, uses the reaction heat of silver nitrate and urea complex to obtain highly stable activated carbon surface to adsorb nano-silver, which is used for pure water Purification and sterilization etc. [0002] technical background [0003] The invention belongs to the activated carbon material modified by nano particle silver in the field of purification, sterilization and the like. [0004] Activated carbon (AC) for deep purification of drinking water at home and abroad is usually mainly loaded with silver. The preparation methods of silver-loaded activated carbon (AC / Ag) mainly include impregnation method, doping method, electrochemical deposition method, reduction method, supercritical water impregnation method, etc. The most industrial applications are ...

AI Technical Summary

Problems solved by technology

However, the process flow of the reduction method is long; multiple washings are required, and the water resource requirements are high; light-shielding, vacuum and other processes are used, and the equipment requirements are high; and the silver particles are mainly distributed on the outer surface and pores of the AC in the form of agglomerates, and the loaded silver The particles are relatively large, and the sterilization efficiency is not high