Iron-silver co-doped biochar with high adsorption capacity and preparation method of iron-silver co-doped biochar

Abstract

The invention discloses a preparation method of iron-silver co-doped biochar with high adsorption capacity, which comprises the following steps: (1) preparing a mixed solution containing Fe ions and Ag ions: adding concentrated H3PO4, an iron compound and AgNO3 into an aqueous solution, and uniformly dispersing the solution; the iron compound is selected from ferric nitrate, ferrous nitrate or a mixture thereof; in the mixed solution, the mass ratio of the iron compound to AgNO3 is (10-50): 1; (2) crushing plant waste biomass, and adding the crushed plant waste biomass and the solution obtained in the step (1) into the lining of the reaction kettle; (3) putting the reaction kettle into a drying oven, raising the temperature to 180-230 DEG C, and maintaining the temperature for 1-2.5 hours; and (4) washing the material until the pH is close to neutral, and then drying. The preparation method disclosed by the invention is simple in steps, is completed by uniformly mixing the required raw materials and putting the mixture into a reaction kettle for one-step hydrothermal carbonization, is short in time consumption and low in chemical reagent consumption, and does not have the inherent problem of exhaust gas emission of a pyrolysis method.

Description

technical field [0001] The invention relates to the technical field of biochar preparation, in particular to an iron-silver co-doped biochar with high adsorption capacity and a preparation method thereof. Background technique [0002] The application of biochar in the field of water treatment has attracted more and more attention, and its abundant surface functional groups (carboxyl, hydroxyl, phenolic hydroxyl, etc.) are active sites for removing pollutants. In recent years, many scholars have greatly improved the adsorption performance of biochar by modifying biochar or loading metals. Especially after loading iron, not only the adsorption capacity is improved, but also the presence of iron endows biochar with magnetic properties, realizing the treatment of pollutants. The purpose of post-solid-liquid separation broadens the application scope of biochar. However, due to certain defects in the preparation technology, the biochar and the supported metals are easily leached,...

AI Technical Summary

Problems solved by technology

However, due to certain defects in the preparation technology, the biochar and the loaded metals are easy to leach, causing secondary pollution of the water body.

[0003] At present, there are not many reports about the simultaneous loading of iron and silver on biochar. The preparation methods are mainly liquid phase reduction method and gel method. For example, the gel method adopted in Chinese patent application CN108115152A first introduces lithium magnesium silicate and polygu A mixed solution containing iron and silver was prepared with amino acid, and a dry gel was formed by heating for a long time, and finally heated at high temperature again to obtain magnetic biochar loaded with iron and silver; however, the preparation process of this method is complicated, and more impurity elements and Chemical agent, heating for many times for a long time consumes a lot of energy, and the economic benefit is low

Another example is the method published by Chinese patent application CN106955667A which adopts the liquid phase reduction method to prepare activated carbon-loaded nano-iron and silver clusters. Although the loading of silver makes the material have certain catalytic properties, the silver metal clusters cause the inhomogeneity of the material. The preparation process Silver ions are easy to form precipitates, which makes the loading efficiency low, and the preparation steps are complicated, the consumption of chemical reagents is large, and the economical practicability is poor.

[0004] At present, the methods for loading metals on biochar mainly include co-precipitation method, co-pyrolysis method, and liquid phase reduction method. The binding ability of the iron-silver co-doped biochar with low risk of metal leaching and high adsorption capacity and its preparation method are lacking.

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