Amidoxime group-containing chitosan modified adsorbent and preparation method thereof

Abstract

The invention discloses a preparation method of a heavy metal adsorbent with a natural high molecular chitosan grafting modified amidoxime group. The preparation method comprises the following basic steps: dissolving chitosan (CTS) used as a raw material in a 1% (mass percent) glacial acetic acid solution, stirring over night, slowly and dropwisely adding alpha-methacryloyl chloride, reacting for some time, regulating the pH value to neutral, performing alcohol washing, and drying to obtain C=C containing modified chitosan (MAc-CTS); and polymerizing the modified chitosan with acrylonitrile, and performing oximation through hydroxylamine hydrochloride to obtain the MAc-CTS / AO adsorbent. The amidoxime group-containing chitosan modified adsorbent prepared by the invention has favorable mercury and cadmium ion adsorption effect, and the adsorption capacities of the adsorbent with respect to mercury and cadmium are respectively up to 418.7mg / g and 93.0mg / g.

Description

technical field [0001] The invention belongs to the fields of oilfield wastewater pretreatment and heavy metal removal, and in particular relates to an amidoxime group-containing chitosan modified adsorbent and a preparation method thereof. Background technique [0002] A large amount of waste will be produced in the process of oilfield exploration and development. The pollutants in oilfield waste mainly include petroleum hydrocarbons, heavy metals, inorganic substances, etc. If they are not treated effectively, they will inevitably cause ecological harm. Although the content of heavy metals in pollutants is not as high as that of crude oil, they are highly toxic and can combine with proteins in the body to accumulate permanently in the human body, which greatly threatens people's health. [0003] With the improvement of human awareness of environmental protection, the problem of heavy metal pollution in oilfield waste has gradually been paid attention to worldwide. In the ...

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Problems solved by technology

[0004] Aiming at the problem of heavy metals in oilfield waste, scientific researchers have done a lot of research, but there are still deficiencies, for example: Chinese patent CN104909442A, an oily sewage treatment agent for oilfields, the oily sewage treatment agent for oilfields described in this patent consists of different proportions of pH adjuster, heavy metal removal agent, flocculant, coagulant aid, hydrophobic agent, decolorizer and other treatment agents are mixed. The disadvantage is that the heavy metal removal agent used is 70% calcium oxide and 30% sodium bisulfite. Although the total mercury and total cadmium content is reduced, the removal effect is not obvious enough, and due to the influence of coexisting metal ions, in a certain To a certain extent, the adsorption of mercury and cadmium is reduced, and the selectivity of the treatment agent is not good or not targeted; Chinese patent CN102504109B, a hydrogel with cyclodextrin side groups and its preparation method, a kind of hydrogel described in this patent Hydrogel with cyclodextrin side groups can effectively adsorb Fe 3+ 、Cr 3+ 、Cu 2+ , Pb 3+ , after constant temperature adsorption for 72 hours, the adsorption capacity of these four metals by the hydrogel is 36.6674mg / g, 2.0324mg / g, 2.1760mg / g, 3.2067mg / g respectively. The disadvantage is that the adsorption capacity of heavy metals is too small, In addition, the adsorption time is too long, which is far from meeting the needs of oilfield waste treatment sites

The chemical precipitation method is simple and cheap, but it is difficult to separate high-concentration wastewater, and the effect is poor; the biggest advantage of electrochemical treatment is that it can recover metals, but it is expensive; the treatment effect of ion exchange is good, and metals can be recovered, but its disadvantage is that Particles are sensitive, and the resin is more expensive; and the method of using traditional adsorbents such as activated carbon adsorption is not suitable for some metals

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