CN-121648883-B - Modified manganese oxide composite material for heavy metal adsorption and preparation method thereof

CN121648883BCN 121648883 BCN121648883 BCN 121648883BCN-121648883-B

Abstract

The invention belongs to the technical field of environmental pollution adsorption treatment, and particularly relates to a modified manganese oxide composite material for heavy metal adsorption and a preparation method thereof. The composition comprises the following raw materials of granular active carbon, manganese source, reducing agent, silicate anchoring phase and carbonate buffer mineral. The invention takes granular active carbon as a framework, forms a high-dispersion manganese oxide active phase through in-situ deposition, triggers silicate gelation through carbon dioxide, builds an inorganic silicon network on the surface of the active phase, firmly anchors active components, enhances mechanical strength, reduces falling off caused by hydraulic flushing, and simultaneously embeds carbonate buffer minerals in the network, can adjust interface acidity, inhibit active components from dissolving out and widens a pH applicable window. The composite material can still maintain stable adsorption performance and long-term operation reliability under the condition of fluctuating water quality, and solves the problems of easy powder falling, easy inactivation, narrow application conditions and the like of the traditional material.

Inventors

SONG HAIYAN
CHENG ZHENYU
HU HAOBIN
LI ZHIJUN
HUANG XINYI

Assignees

陇东学院

Dates

Publication Date: 20260508
Application Date: 20260207

Claims (5)

1. The modified manganese oxide composite material for heavy metal adsorption is characterized by comprising the following raw materials of granular active carbon, manganese source, reducing agent, silicate anchoring phase and carbonate buffer mineral; the particle size of the granular activated carbon is 1-1.6 mm; The manganese source is KMnO 4 ; the reducing agent is any one of glucose and ascorbic acid; The silicate anchoring phase is water glass solution, and the mass fraction of the water glass solution is 2-5wt%; The carbonate buffer mineral is any one of CaCO 3 , dolomite powder and shell powder, and the particle size D 50 =1-10 mu m; the modified manganese oxide composite material for heavy metal adsorption is prepared by the following steps: S1, placing granular activated carbon into deionized water circulation for washing treatment, then washing with NaHCO 3 , washing with deionized water to be neutral, and drying to obtain pretreated activated carbon; S2, placing the pretreated activated carbon in the step S1 into a manganese source solution, stirring and impregnating, filtering and leaching the solution without washing to obtain impregnated activated carbon; s3, adding the impregnated activated carbon into deionized water again to form slurry, then slowly dropwise adding a reducing agent solution under the stirring condition, continuing to react after the dropwise adding is finished, and filtering and washing after the reaction to obtain the in-situ deposited activated carbon; S4, placing the activated carbon deposited in situ in the step S3 in a silicate anchoring phase, stirring and soaking at room temperature, draining after soaking, placing in a closed reactor, introducing CO 2 , controlling the temperature, reacting, immediately adding carbonate buffer mineral after the reaction is finished, stirring and dispersing uniformly, standing and ageing at room temperature, filtering and washing until the pH of the effluent is neutral and the conductivity is stable, drying and curing again to obtain the modified manganese oxide composite material.
2. The modified manganese oxide composite material for heavy metal adsorption according to claim 1, wherein in the step S2, the ratio of the amount of the pretreated activated carbon to the amount of the manganese source solution is 1 g:10-15 ml.
3. The modified manganese oxide composite material for heavy metal adsorption according to claim 1, wherein in the step S3, the ratio of the usage amount of the impregnated activated carbon to the usage amount of the deionized water is1 g:8-12 mL, and the ratio of the usage amount of the impregnated activated carbon to the usage amount of the reducing agent solution is1 g:5-12 mL.
4. The modified manganese oxide composite material for heavy metal adsorption according to claim 1, wherein in the step S3, the stirring condition is 150-250 rpm.
5. The modified manganese oxide composite for heavy metal adsorption according to claim 1, wherein in the step S4, the ratio of the usage amount of the in-situ deposited activated carbon to the silicate anchoring phase is 1 g:8-12 ml, and the ratio of the mass usage amount of the in-situ deposited activated carbon to the mass usage amount of the carbonate buffer mineral is 1 g:0.02-0.03 g.

Description

Modified manganese oxide composite material for heavy metal adsorption and preparation method thereof Technical Field The invention belongs to the technical field of environmental pollution adsorption treatment, and particularly relates to a modified manganese oxide composite material for heavy metal adsorption and a preparation method thereof. Background The heavy metal polluted water body mainly comes from industrial wastewater discharge such as mining, metallurgical electroplating, chemical pharmacy and the like and mine runoff seepage, and heavy metal ions such as cadmium, lead, chromium, arsenic and the like have bioaccumulation, persistent toxicity and are difficult to naturally degrade, after entering the water body, the balance of an aquatic ecosystem can be destroyed, and the human health can be endangered through food chain enrichment, so that the efficient treatment of the heavy metal polluted water body is a core research direction and engineering requirement in the field of water environment restoration. The adsorption method is a mainstream technical means for treating heavy metal polluted water in the current practical engineering because of simple operation, high treatment efficiency, controllable cost and easy realization of heavy metal resource recovery. The granular active carbon is one of the most commonly used adsorption carriers because of developed pore structure, high mass transfer efficiency, good formability and easy adaptation to engineering devices such as a fixed bed, a filter column and the like, but the adsorption of heavy metal ions mainly depends on physical adsorption and weak surface complexation, has weak specific adsorption capacity, has poor adsorption selectivity and stability under the conditions of water acid-base fluctuation and coexistent ion interference, is difficult to meet the requirement of deep purification by single use, and the manganese oxide is rich in active groups such as hydroxyl groups on the surface, can realize the efficient capture of the heavy metal ions through multiple functions such as surface complexation, ion exchange, redox, morphological regulation and the like, has obviously better adsorption specificity and capacity than the active carbon, is in powder form, has low mechanical strength, easy agglomeration, causes secondary pollution due to direct addition and easy loss, is easy to dissolve out and deactivate in an acidic water body, and can not be independently applied to an actual engineering water treatment system. In order to give consideration to the engineering suitability of the activated carbon and the high-efficiency adsorptivity of the manganese oxide, the prior art adopts the modes of physical mixing, simple coating and the like to load the manganese oxide on the surface of the activated carbon to prepare the composite adsorption material, which becomes a main improvement idea in the field. The preparation process has the obvious defects that the active phase of the manganese oxide is poor in dispersibility on the surface of a carrier, is only physically combined with active carbon, is weak in binding force, is easy to fall off and fall off powder under the working conditions of hydraulic flushing, particle shearing friction, repeated filling operation and the like of an actual water body, so that the adsorption activity of the material is fast attenuated, the water body is secondarily turbid, and the long-term operation stability is poor. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a modified manganese oxide composite material for heavy metal adsorption and a preparation method thereof. Solves the problems of easy falling of active components, unstable adsorption performance, insufficient adaptability of wide working conditions and the like of the existing adsorption material under the actual engineering working conditions of large acid-base fluctuation, strong shearing and scouring and obvious coexisting ion interference. The technical effect of the invention is realized by the following technical scheme that the modified manganese oxide composite material for heavy metal adsorption comprises the following raw materials of granular active carbon, manganese source, reducing agent, silicate anchoring phase and carbonate buffer mineral; preferably, the particle size of the granular activated carbon is 1-1.6 mm; Preferably, the manganese source is KMnO 4; preferably, the reducing agent is any one of glucose and ascorbic acid; preferably, the silicate anchoring phase is water glass solution, wherein the mass fraction of the water glass solution is 2-5wt% calculated by SiO 2; Preferably, the carbonate buffer mineral is any one of CaCO 3, dolomite powder and shell powder, and the particle size D 50 =1-10 μm; preferably, another aspect of the present invention is to provide a method for preparing a modified manganese oxide composite material for heavy metal adsorption, which specifical