Modified walnut-shell adsorbent containing double amidoxime groups and preparation method thereof

Abstract

The invention relates to a modified walnut-shell adsorbent containing double amidoxime groups and a preparation method thereof. The preparation method of the modified walnut-shell adsorbent comprises: taking a biomass material walnut shells as an initial raw material, performing pretreatment, firstly reacting with a sodium hydroxide solution and a chloropropylene oxide etherifying agent, reacting the obtained primary-modified walnut shell particles with a diethylenetriamine cross-linking agent for introducing of amino groups, then performing an induced reaction on the obtained secondly-modified walnut-shell particles with acrylonitrile, and then performing further modification reaction on the obtained thirdly-modified walnut-shell particles with a mixed solution of hydroxylamine hydrochloride and sodium carbonate, and performing post-processing, so as to prepare the finished product of the modified walnut-shell adsorbent containing double amidoxime groups, wherein the finished product has brownish yellow appearance and is in the state of particles. The adsorbent provided by the invention has excellent adsorption capacity, is high in removing rate on dye in printing and dyeing waste water and substantial in treatment effect on heavy metal wastewater; the raw materials demanded by the preparation method provided by the invention is wide in resource, and the prepared finished product is excellent in comprehensive performances.

Description

technical field [0001] The invention belongs to the field of preparation of modified adsorbent materials, in particular to a modified walnut shell adsorbent containing bisamidoxime groups and a preparation method thereof. Background technique [0002] With the continuous acceleration of the construction and development of township industries and rural cities and towns in my country, the discharge of various industrial wastewater and domestic sewage is increasing, especially the printing and dyeing wastewater and heavy metal polluted wastewater have increasingly serious impacts on the ecological environment and human health, and they should be treated accordingly It has become an increasingly prominent issue in environmental governance. The traditional treatment methods for these wastewater include electrochemical method, coagulation precipitation method, oxidation method, membrane separation method and activated carbon adsorption method, among which activated carbon adsorptio...

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Problems solved by technology

[0003] In the article "Preparation of Grafted Amidoxime Resin / SiO2 Functional Composite Particles" published in "Applied Chemistry", 2010, 27 (3): 313-316, Gao Xuechao et al. proposed that based on KH570 modified silica gel particles Carry out acrylonitrile grafting, and then undergo amidoxime reaction, so as to prepare the adsorption material containing amidoxime group; but its disadvantages are: poor adsorption effect, long adsorption saturation time and low grafting degree

Chinese patent application CN101357325A discloses "a spherical cellulose chelating adsorbent containing amidoxime group and carboxyl group and its preparation method", and its preparation process includes graft copolymerization, saponification and amidoximation to obtain the finished product of the adsorbent , but there are still shortcomings such as low grafting degree, low material adsorption selectivity and poor adsorption effect.

Chinese patent application CN101596449A discloses "a method for preparing an amidoxime-based uranium-extracting adsorbent", which proposes to prepare acrylonitrile powder and sol-gel to prepare titanium dioxide by blending oximation to obtain a hybrid amidoxime-based uranium-extracting material, but still Insufficient mechanical strength and low adsorption capacity

Chinese patent application CN103223332A discloses "a modified silica gel adsorbent containing amidoxime group and its preparation method" and Chinese patent application CN103223333A discloses "a silica gel adsorbent containing bisamidoxime group and its preparation method" ", have proposed the preparation of modified silica gel adsorbent schemes, although compared with the raw materials, the adsorption performance has been greatly improved, but the maximum adsorption capacity after modification is only 20mg / g and 30mg / g respectively, and there are still some problems. big limitations

Chinese patent application CN200510040485.8 discloses "a method of using straw to prepare cationic adsorbent", which proposes to modify the crushed straw with citric acid, reflux for 12 hours, filter, and wash with distilled water until neutral to obtain a finished product. But the whole process is complex, the amount of modified additives is large and the cost is high

Chinese patent application CN201010243990.3 discloses "a method for preparing cationic adsorbent with plantain taro dregs", which proposes to stir the lye and plantain taro dregs first, and then add epoxypropyltrimethylammonium chloride for stirring 30min, after a little reaction in the oven, adjust the pH to neutral with hydrochloric acid, filter, wash, and vacuum-dry to obtain the finished product.

[0006] In order to overcome the deficiencies of the prior art, the applicant proposed "a method for preparing a modified walnut shell cationic adsorbent" in Chinese patent application 201310324695.4. The modified adsorbent prepared by this method is a modified walnut containing polyamino groups Shell cationic adsorbent has a good effect on removing reactive brilliant red K-2BP dye in printing and dyeing wastewater, but there are still obvious deficiencies: first, the amount of grafted amino groups on the surface of the adsorbent prepared by this modification method is less, and its effect on The adsorption capacity of dyes is still insufficient; the second is that only amino groups are grafted on the surface of the modified adsorbent, so the types of wastewater treated with the modified adsorbent are extremely limited, such as the efficiency of adsorption treatment of wastewater containing cationic dyes and heavy metals extremely low

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