CN103551119A - Oyster shell heavy metal ions absorbent and preparation method thereof - Google Patents

Abstract

The invention relates to an oyster shell composite heavy metal adsorbent, which is characterized in that: oyster shells are ground into powder, passed through a 100-mesh sieve, modified by adding 0.4% SDS solution, filtered and dried, and modified oyster shell powder is mixed with bentonite Compounding and mixing at a weight ratio of 2:1, extrusion granulation, spheronization, and calcination to obtain spherical particle composite heavy metal adsorbents.

Description

A kind of oyster shell heavy metal adsorbent and preparation method thereof

technical field

The invention relates to a deep processing technology for by-products of aquatic product processing, and develops a novel water quality heavy metal adsorbent and a preparation method thereof.

Background technique

The annual output of shellfish in my country accounts for more than 60% of the world's output, ranking first in the world. While these shellfish resources drive the rapid development of coastal economy, they will inevitably produce a large number of discarded shells. If these discarded shell resources are not well utilized, they will also bring a large amount of solid waste and have a negative impact on the environment.

Oysters have left and right shells, the right shell is also called the upper shell, and the left shell is also called the lower shell. Oyster shells are divided into 3 layers according to the formation method and tissue structure: the outermost layer is the cuticle or cortex (periostracum), which contains conchoids and has strong resistance to corrosion by external chemicals; the middle layer is The prismatic layer is composed of calcareous precipitates with polygonal prismatic crystals, containing a large number of pores of 2-10 μm; the inner layer is the pearl layer, mainly composed of calcite, which can gradually thicken. As the age increases, the layers of the nacre will increase. Due to the special physical structure of oyster shells, there are a large number of interconnected pores inside, including a large number of 2-10 μm micropores, which can produce a variety of different functional pore structures after treatment, so that they have strong adsorption capacity and exchange capacity. It can well absorb heavy metals, organic phosphorus and other components in aquaculture water, and has a good water quality clarification effect. About 1 million tons of discarded oyster shells are produced along the coast of China every year. These "accumulated" raw materials make the product cost low, developable, and have strong market competitiveness. Using oyster shell powder to treat aquaculture water and turning oyster shell waste into treasure can effectively improve the aquaculture environment and increase fish food safety. Treating aquaculture water with oyster shell powder is a treatment technology with simple operation and low investment. Using this technology to treat aquaculture water has the advantages of high efficiency, low consumption, and no secondary pollution. It can effectively reduce heavy metals, nitrogen, phosphorus, etc. in aquaculture water. The content of pollutants can improve the aquaculture environment. At present, there are relatively few studies on the use of this method to treat aquaculture water, and it has broad space and good prospects.

Contents of the invention

The invention relates to an oyster shell composite heavy metal adsorbent, which is characterized in that: oyster shells are ground into powder, passed through a 100-mesh sieve, modified by adding 0.4% SDS solution, filtered and dried, and modified oyster shell powder is mixed with bentonite Compounding and mixing at a weight ratio of 2:1, extrusion granulation, spheronization, and calcination to obtain spherical particle composite heavy metal adsorbents.

The technical problem to be solved by the invention is to enhance the heavy metal adsorption efficiency of the oyster shell and to develop an easy-to-apply product form. The preparation method comprehensively applies three methods of sodium hexadecylsulfonate (SDS) modification, compounding with bentonite, and high-temperature calcination, which effectively improves the heavy metal adsorption capacity of oyster shell powder; and uses the viscosity characteristics of bentonite, The small spherical particle adsorbent is prepared by extrusion granulation, spheronizing and calcining, which makes the adsorbent easy to transport, store and apply. The method has simple process, low cost and good applicability.

The method for preparing the heavy metal adsorbent of novel oyster shells in the present invention mainly includes the following steps.

1. Oyster shell crushing: remove impurities, wash the oyster shell, dry, pulverize, and pass through a 100-mesh sieve to obtain oyster shell powder.

2. Oyster shell modification: Weigh oyster shell powder, add 2 times the volume of 0.4% sodium hexadecylsulfonate (SDS) solution, stir at 60°C for 2 hours, filter, and dry at 60°C. Crushed through a 100-mesh sieve, dried and sealed for later use.

3. Compounding: compound and mix the modified oyster shell powder and bentonite at a weight ratio of 2:1.

4. Shaping: Mix the compound raw materials with water, extrude, granulate, and spheronize to obtain spherical particles with a particle size of 4-6 mm.

5. Calcination: Spherical granular pellets are calcined at 550-600°C for 2 hours, taken out and cooled, sealed and packaged, which is the oyster shell heavy metal adsorbent.

The oyster shell water quality heavy metal adsorbent provided by the invention has the following characteristics.

1. It has a good adsorption effect on heavy metals such as Cu ²⁺ , Zn ²⁺ , Pb ²⁺ , Cd ²⁺ , and Cr(Ⅵ).

2. Spherical adsorption beads have the characteristics of good fluidity, easy packaging, easy storage, easy transportation, and not easy to break.

3. The water quality improver has low cost, simple preparation method, good effect and no secondary pollution during use.

Detailed ways

In order to facilitate the understanding of the present invention, examples are specifically cited to further explain the present invention, but not to limit the present invention in any way.

1. Preparation of oyster shell powder: 120 kg of oyster shells were cleaned and dried, pulverized with a universal grinder, and sieved with a 100-mesh sieve to obtain 100 kg of oyster shell powder.

2. Modification of oyster shell powder: put 100kg of oyster shell powder into a blending tank, add 200L of 0.4% sodium hexadecylsulfonate (SDS) preheated at 60°C, stir at a constant temperature of 60°C for 2 hours, and filter with plate and frame Water is removed to obtain modified oyster shell powder, which is dried in an oven at 60° C. and pulverized by a universal grinder to obtain modified oyster shell powder.

3. Compounding: In a mixer, add 100 kg of modified oyster shell powder and 50 kg of bentonite, and stir for 30 minutes to fully mix the two samples.

4. Modeling: Add 30 kg of water to the mixed composite powder, stir evenly, add water to the compound raw material and knead it into a block, put it in an extrusion granulator for granulation, and carry out extrusion granulation, and the granulation particle size is 4 -6 mm, transfer the particles to a spheronizer for spheronization to obtain spherical particles with a particle size of 4-6 mm.

5. Calcination: Put spherical granular pellets in a muffle furnace, adjust the temperature to 550-600°C and calcinate for 2 hours, take them out to cool, seal and pack them, and obtain the oyster shell heavy metal adsorbent product. The pellets were subjected to a heavy metal adsorption test, and the results showed that the adsorption rates of Cu ²⁺ , Zn ²⁺ , Pb ²⁺ , Cd ²⁺ , and Cr(Ⅵ) were 96.12%, 87.32%, 85.31%, and 88.32%, respectively. %, 88.44%.

Claims (3)

1. The present invention relates to an oyster shell heavy metal adsorbent and a preparation method thereof, characterized in that: oyster shell powder is modified, compounded with bentonite, extruded, granulated, spheronized, and calcined to obtain a particle size of 4 -6 mm spherical granular heavy metal adsorbent. 2. In claim 1, the oyster shell modification method is characterized in that: add 0.4% sodium hexadecylsulfonate (SDS) solution with a concentration of 2 times the volume and fully stir with oyster shell powder, and stir at a constant temperature of 60°C After filtering for 2 hours, drying at 60°C and crushing, the modified oyster shell powder is obtained. 3. In claim 1, the compounding of modified oyster shell powder and bentonite is characterized in that: the modified oyster shell powder and bentonite are fully mixed in a weight ratio of 2:1.