Preparation method of dithiocarboxylated straw, product and application of dithiocarboxylated straw as heavy metal adsorbent

Abstract

The invention discloses a preparation method of dithiocarboxylated straw, a product and application of the dithiocarboxylated straw as a heavy metal adsorbent. The method comprises the following stepsof: carrying out impurity removal, cleaning, drying, crushing, sieving and other pretreatment on straws, adding a certain amount of NaOH and distilled water, mixing and stirring for a certain time, adding CS2, continuing to stir and react for a period of time, heating, and continuing to react, and standing the mixed solution, carrying out suction filtration, washing the filter residue with distilled water until the pH value of the filtrate is constant, and drying the filter residue to constant weight, thereby obtaining the dithiocarboxylated straw. Through chemical modification, a functionalgroup dithiocarboxyl is grafted into a straw molecular structure, so that the adsorption performance of the straw is greatly improved, and the removal rate of the straw to heavy metals is remarkably improved.

Description

technical field [0001] The invention relates to the technical field of heavy metal sewage treatment, in particular to a preparation method and product of dithiocarboxylated straw and its application as a heavy metal adsorbent. Background technique [0002] With the rapid development of electroplating, mining, tanning, battery and other industries, a large amount of wastewater containing heavy metals such as zinc, copper, nickel, mercury, cadmium, lead, and chromium has been produced, and its untreated arbitrary discharge will affect surface water and groundwater. and serious pollution of the soil environment. Adsorption is currently one of the most economical and effective methods for removing heavy metals in wastewater. Adsorbents commonly used to remove heavy metals in water, such as activated carbon, adsorption resin, and activated aluminum, are generally expensive or have low adsorption capacity. The production of crop straw in my country is large and the utilization r...

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Problems solved by technology

[0004] In the patent CN103447005, epichlorohydrin is first used to react with the hydroxyl groups in the straw for cross-linking. Although the hydrophilicity of the straw is improved, a certain amount of hydroxyl groups is also consumed at the same time; because the added carbon disulfide and sodium hydroxide mainly interact with the The sulfonation reaction of hydroxyl groups in the straw reduces the effective amount of hydroxyl groups participating in the sulfonation reaction, and the addition of epichlorohydrin increases the types and amounts of reactants. The adsorption time of the straw adsorption materials thus prepared is longer, and the highest adsorption The efficiency and maximum adsorption capacity also need to be further improved.

[0005] In the patent CN109012617A, after soaking the straw with a mixed solution of sodium hydroxide and thiourea, the modifier polyamine, aldehyde and catalyst triethylamine (or mercaptoethylamine) were added to react, and the added polyamine and aldehyde mainly Mannich reaction with hydroxyl in straw to introduce amine group, and sulfonation reaction of amine group with carbon disulfide and sodium hydroxide to introduce dithioamino group. This method is complicated and has many influencing factors, so it is difficult to Control the production process

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