CN110801808A

CN110801808A - Preparation method and application of coffee grounds biochar

Info

Publication number: CN110801808A
Application number: CN201911073952.5A
Authority: CN
Inventors: 张新波; 张永超; 张丹; 李超灿; 温海涛; 王晓
Original assignee: Tianjin Chengjian University
Current assignee: Tianjin Chengjian University
Priority date: 2019-11-06
Filing date: 2019-11-06
Publication date: 2020-02-18

Abstract

The invention provides a preparation method and application of coffee residue biochar. The antibiotics in the wastewater are removed by adsorbing the sulfanilamide antibiotics through the combined action of the carbonized part and the non-carbonized part of the obtained charcoal. The invention has the beneficial effects that: the method is simple to operate and low in cost, and meanwhile, the coffee grounds which are not reasonably disposed can be recycled, so that the waste is changed into valuable.

Description

Preparation method and application of coffee grounds biochar

Technical Field

The invention relates to the field of carbon materials and environmental protection, in particular to a preparation method and application of coffee grounds biochar.

Background

Antibiotics have attracted increasing attention worldwide as emerging pollutants. The widespread use of antibiotics in humans and animals leads to their constant release into the environment and subsequent generation and dissemination of resistance genes. However, the antibiotics cannot be completely removed by the current wastewater treatment plant, and in recent years, a plurality of researches on the removal of the antibiotics exist, wherein the adsorption is an economic and efficient means.

The biochar is a solid material produced by pyrolysis conversion of a biomass raw material under the condition of complete anaerobic or partial anoxic condition, and has wide application prospects in the aspects of carbon fixation, soil improvement, polluted environment restoration and the like due to the characteristics of compact pore structure, abundant surface functional groups, a large amount of surface charges, high aromatic structure, higher chemical and biological stability and the like, so that the biochar is widely concerned by many scientific researchers. Compared with activated carbon, the biochar is cheaper and has wide sources, and simultaneously has abundant surface functional groups, and the surface functional groups can play an important role in the adsorption process.

Coffee is consumed in about 500 billion cups per year as one of the most popular beverages worldwide. Whereas a large amount of coffee grounds are produced during the production of such beverages; statistically, the annual production of coffee grounds is about 600 million tons worldwide. Currently, coffee grounds have no market for corresponding disposal, and can only be incinerated in landfills or incinerated, which may cause serious environmental problems due to the large amount of organic compounds, such as fatty acids, lignin, cellulose and hemicellulose. However, the high organic compounds make coffee grounds attractive as biomass, and biofuels and valuable products, such as biochar, can be obtained.

Disclosure of Invention

The invention aims to provide a preparation method of coffee grounds biochar and application of the coffee grounds biochar in removal of sulfonamide antibiotics.

In order to solve the technical problems, the invention adopts the technical scheme that: firstly, drying collected coffee grounds in the natural ventilation condition, drying the coffee grounds in an oven for 24 hours, carbonizing the dried coffee grounds in an oxygen-limited environment condition to obtain a biochar primary product, finally, acidifying the biochar primary product with 1mol of hydrochloric acid for 4 hours in a ratio of 1:20, washing the acidified biochar with deionized water to be neutral, and filtering, drying, crushing and sieving the product to obtain the biochar of the coffee grounds.

The temperature rise rate in the carbonization process of the obtained biochar primary product is 4-6 ℃/min, the carbonization temperature is 300-700 ℃, and the carbonization time is 2 h.

The aperture of the screen used for sieving is 100 meshes.

Adding the obtained coffee grounds biochar into sulfonamide antibiotic solution with the initial concentration of 5-2000 mug/L, shaking and mixing for 24 hours at 25 ℃, and carrying out solid-liquid separation after a filter membrane.

The above-mentioned sulfonamide antibiotics are sulfadiazine and sulfamethoxazole.

The invention has the beneficial effects that:

1. the raw material coffee grounds selected by the invention can effectively solve the problem of disposal of the coffee grounds, and can be recycled, so that the waste is changed into valuable.

2. The synthesis method is simple, low in cost, short in time consumption in the oxygen-limited carbonization process, low in energy consumption and low in process operation requirement.

3. The coffee grounds biochar produced by the invention can be used for removing sulfonamide antibiotics in water environment, and under the condition that the initial concentration is 500 mug/L, the maximum adsorption capacity to sulfamethoxazole can reach 130.1 mug/g, and the maximum adsorption capacity to sulfadiazine can reach 121.5 mug/g.

Drawings

FIG. 1 is an X-ray diffraction pattern of the biochar from coffee grounds synthesized in examples 1 and 2;

FIG. 2 is a scanning electron micrograph of examples 1 and 2;

FIG. 3 shows the adsorption kinetics of sulfamethoxazole by the synthetic coffee grounds biochar in example 1;

FIG. 4 is the adsorption kinetics of sulfadiazine on charcoal of coffee grounds synthesized in example 2.

Detailed Description

The invention is described in further detail below with reference to the following figures and detailed description:

example 1

Firstly, drying collected coffee grounds in the natural ventilation condition, drying the coffee grounds in an oven for 24 hours, then weighing 90g of dried coffee grounds, carbonizing the coffee grounds in an oxygen-limited environment condition, wherein the heating rate is 5 ℃/min, the carbonization temperature is 400 ℃, and the carbonization time is 2 hours, so as to obtain a biochar primary product, finally acidifying the biochar primary product with 1mol of hydrochloric acid for 4 hours in a ratio of 1:20, washing the acidified biochar with deionized water to be neutral, and filtering, drying, crushing and sieving the washed biochar to obtain the coffee grounds biochar. The X-ray diffraction pattern and the electron microscope scanning pattern of the obtained coffee grounds biochar are respectively shown as biochar-400 in figure 1 and biochar-400 in figure 2. Adding the obtained coffee grounds biochar into sulfamethoxazole solution with the initial concentration of 500 mu g/L, shaking and mixing for 0-72h at the temperature of 25 ℃, and carrying out solid-liquid separation after passing through a filter membrane. The adsorption kinetics of the coffee grounds charcoal on sulfamethoxazole are shown in figure 3.

Example 2

Firstly, drying collected coffee grounds in the air under the natural ventilation condition, drying the coffee grounds in an oven for 24 hours, then weighing 90g of dried coffee grounds, carbonizing the coffee grounds under the oxygen-limited environmental condition, wherein the heating rate is 5 ℃/min, the carbonization temperature is 500 ℃, and the carbonization time is 2 hours, so as to obtain a biochar primary product, finally, acidifying the obtained biochar primary product with 1mol of hydrochloric acid for 4 hours in a ratio of 1:20, washing the acidified biochar with deionized water to be neutral, and filtering, drying, crushing and sieving the obtained biochar to obtain the coffee grounds biochar. The obtained coffee residue biochar has X-ray diffraction pattern and electron microscope scanning pattern, which are shown as biochar-500 in figure 1 and biochar-500 in figure 2, respectively. Adding the obtained coffee grounds biochar into sulfadiazine solution with the initial concentration of 500 mug/L, shaking and mixing for 0-72h at the temperature of 25 ℃, and carrying out solid-liquid separation after passing through a filter membrane. The adsorption kinetics of the obtained coffee grounds charcoal on sulfadiazine are shown in figure 4.

Claims

1. The preparation method of the coffee grounds biochar is characterized by comprising the following steps:

step one, collecting and air-drying coffee grounds;

step two, drying the coffee grounds obtained in the step one;

step three, carbonizing the coffee grounds dried in the step two under the condition of an oxygen-limited environment to prepare a biochar primary product;

step four, acidifying the charcoal primary product obtained in the step three;

and step five, washing the acidified biochar to be neutral by using deionized water according to the step four, and filtering, drying, crushing and sieving to obtain the coffee grounds biochar.

2. The method for preparing coffee grounds biochar according to claim 1, wherein the drying in the step two is drying in an oven for 24 hours.

3. The method for preparing biochar from coffee grounds as claimed in claim 1, wherein the carbonization in step three is carried out in a muffle furnace, the temperature rise rate is 4-6 ℃/min, the carbonization temperature is 300-700 ℃, and the carbonization time is 2 h.

4. The method for preparing biochar from coffee grounds according to claim 1, wherein the acidification condition in the step four is to acidify the biochar primary product with 1mol of hydrochloric acid in a ratio of 1:20 for 4 hours.

5. The method for preparing coffee grounds biochar as claimed in claim 1, wherein the aperture of the sieving screen in the fifth step is 100 meshes.

6. Use of a coffee grounds biochar as claimed in claim 1, wherein the coffee grounds biochar is used as an adsorbent to remove sulfonamide antibiotics from wastewater.

7. The use of the coffee grounds biochar as claimed in claim 6, wherein the adding ratio of the adsorbent to the wastewater is 1: 300.

8. Use of a coffee grounds biochar as claimed in claim 6, wherein is the coffee grounds biochar? Adding into 5-2000 μ g/L sulfanilamide antibiotic solution, shaking and mixing at 25 deg.C for 24 hr, and filtering with filter membrane for solid-liquid separation.

9. The use of the coffee grounds biochar as claimed in claim 6, wherein the sulfonamide antibiotics are sulfadiazine and sulfamethoxazole.