A kind of nano silver-lignin carbon composite material and its preparation method and application

Abstract

The invention belongs to the technical field of catalysts, and discloses a nano-silver-lignin-carbon composite material and a preparation method and application thereof. The method of the present invention comprises the following steps: (1) after the lignin is nanosized under the action of a nanometerizing agent, a sulfonating agent is added to carry out a sulfonation reaction to obtain a sulfonated lignin; (2) reacting with formaldehyde and an aminating agent to obtain a sulfonated lignin (3) react with silver salt to obtain nano-silver; (4) mix with carbonization activator and carbonize at high temperature to obtain nano-silver-lignin-carbon composite material; the mass ratio of each component is as follows: lignin 100 parts; 1-10 parts of nanometerization reagent; 5-20 parts of sulfonating reagent; 50-150 parts of formaldehyde; 50-150 parts of amination reagent; 10-40 parts of silver salt; The composite material of the invention has high nano-silver loading capacity and good recycling performance, and can be applied to the fields of catalytic materials, bactericidal materials, biological materials, optical materials and the like.

Description

technical field [0001] The invention belongs to the technical field of catalysts, in particular to a nano-silver-lignin carbon composite material and its preparation method and application. Background technique [0002] Precious metal catalysts are widely used in many aspects such as industrial catalysis, new energy research, automobile exhaust purification and conversion, catalytic hydrogen production and petroleum processing, and are considered to be "vitamins of today's industry". Currently commonly used precious metals are platinum, palladium, rhodium, silver, ruthenium and so on. Their d electron orbitals are not filled, the surface is easy to adsorb reactants, and the strength is moderate, which is conducive to the formation of "active intermediates" in the reaction process, has high catalytic activity, and also has high temperature resistance, oxidation resistance, corrosion resistance, etc. Comprehensive good features. Therefore, the research on the preparation and...

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Problems solved by technology

[0006] Milczarek G et al. used sodium lignosulfonate to prepare nano-silver sol with an average particle size of 46nm, which can be used as a metal colorimetric probe to detect the concentration of metal ions [Colloids and Surfaces B: Biointerfaces, 2013, 105: 335-341.], However, sodium lignosulfonate cannot be used as a carrier of nano-silver because of its strong water solubility. The obtained nano-silver can only be used once and is difficult to recycle.

And prepare nano-silver with unmodified alkali lignin [ACS SustainableChemistry&Engineering, 2018, 6(6): 7695-7703; International journal of biologicalmacromolecules, 2016, 82: 39-47; ACS applied materials&interfaces, 2014, 6(18 ): 16147-16155.], because of its serious agglomeration, it needs to be dissolved in alkaline or organic solvents to fully utilize the phenolic hydroxyl groups on the lignin, so that the compound needs to be precipitated from the reaction system by adding acidifying reagents after the reaction However, the oxygen-containing functional groups on lignin are difficult to form a stable coordination with silver ions, which makes nano-silver easy to detach during use, and lignin is soluble in alkaline solution and some Organic solvents, poor mechanical strength, these will lead to the difficulty of reusing the nano-silver-lignin composites prepared directly from alkali lignin

Therefore although lignin can be used as the reducing agent and stabilizer for preparing nano-silver, and the carrier that obtains nano-silver is prepared, but the method that lignin plays these three effects simultaneously in the nano-silver preparation process still has more shortcomings and limitations. insufficient

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