A kind of silica gel adsorbent for adsorbing heavy metal ions and preparation method thereof

Abstract

The invention relates to a silica gel absorbent for absorbing heavy metal ions and a preparation method thereof, and discloses a preparation method of a N,N-di(phosphinemethyl) bis-substituted aminodithioformic acid functionalized silica gel absorbent and the adsorption effect of the absorbent on heavy metal ions such as cadmium, copper, nickel, lead, and the like. The preparation of the adsorbent comprises the following steps: reacting carbon disulfide with amino methane phosphonic acid, grafting the reaction products to the surface modified silica gel, and finally carrying out acidification. The synthesis conditions of the method are mild and efficient. The provided absorbent has a large adsorption amount and good selectivity on heavy metal ions such as mercury, copper, nickel, lead, and the like. Moreover, the metals can be recycled through a proper treatment, and the resources are regenerated and circularly used. The silica gel absorbent can be used to process and recycle wastewater containing heavy metals, can also be used to separate, enrich, and remove heavy metals in medicinal materials and environment analysis, and has a wide application prospect. The provided preparation method and prepared adsorbent will not generate secondary pollution to the environment.

Description

technical field [0001] The invention discloses a preparation method of a silica gel adsorbent functionalized with N, N-bis(phosphinemethyl) disubstituted dithiocarbamic acid and its adsorption to cadmium, copper, nickel, lead and other heavy metal ions. Background technique [0002] With the continuous acceleration of my country's industrialization process, environmental pollution, especially water pollution, is becoming more and more serious. Industrial wastewater containing a large amount of heavy metal ions such as cadmium, copper, lead, and nickel is discharged into rivers, which not only causes great harm to the ecological environment and human beings. , and caused a waste of these metal resources; at present, for water bodies containing heavy metal ions, the technologies that can be used include chemical precipitation, electrolysis, ion exchange, adsorption, etc.; among these treatment technologies, solid phase extraction technology based on chelating resin It has great ...

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Problems solved by technology

[0003] The thiocarbamate chelating resins reported in literature and patents mostly adopt hydrophobic skeletons such as polyvinyl chloride and polystyrene, which cause the infiltration rate of chelating resins in aqueous solution to be small, so that the ions in the inside of chelating resins Diffusion is hindered, which affects the adsorption speed and efficiency, and this type of material has poor selective adsorption function for heavy metal ions; inorganic / organic materials based on silica gel have become one of the current research hotspots, not only because silica gel has good mechanical properties. Processing strength, high chemical stability and thermal stability, and because of the rich silanol on the surface can show good hydrophilicity, which greatly improves the adsorption performance of the resin; as we all know, when heavy metal ions and can provide When the Lewis base of the electron forms a relatively stable coordination bond, it can be removed from the solution in the form of a chelate; the functional group that can provide a lone pair of electrons generally includes coordination atoms such as sulfur, oxygen, nitrogen, and phosphorus, which can The properties of the Lewis base that provides the lone pair of electrons determine its selectivity when it coordinates with heavy metal ions to form a chelate; at present, a series of chelating resins containing functional groups such as oxygen, nitrogen, phosphorus, and sulfur atoms have been developed, which are Widely used in the treatment of wastewater containing heavy metal ions; patent CN 101817898 discloses an iminobis(methylene phosphorous acid) chelating resin and its application in the treatment of electroplating waste liquid

Patent 200710019808.4 discloses a preparation method of N, N-di(carboxymethyl) disubstituted dithiocarbamate chelating resin and its selective adsorption to heavy metal ions such as nickel and zinc; However, the adsorption effect on heavy metal ions such as copper, nickel, and lead still needs to be improved; accordingly, we used silica gel as a substrate to prepare a silica gel adsorbent modified by phosphinomethyl-substituted thiocarbamate groups. And this heavy metal adsorbent has no related reports; the preparation method of the present invention and the prepared adsorbent will not cause secondary pollution of the environment

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