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CN-121972133-A - Method for preparing heavy metal adsorbent by modifying biomass charcoal and heavy metal adsorbent

CN121972133ACN 121972133 ACN121972133 ACN 121972133ACN-121972133-A

Abstract

The invention provides a method for preparing a heavy metal adsorbent by modifying biomass charcoal and the heavy metal adsorbent, the method comprises the steps of selecting biomass charcoal raw materials, crushing, screening the crushed biomass charcoal raw materials, and drying the screened biomass charcoal raw materials; preparing a modifier solution with the concentration of 0.5 mol/L-1 mol/L, uniformly stirring the modifier solution, mixing the modifier solution and the dried biomass charcoal raw material according to a preset mass ratio, uniformly stirring the mixture, carrying out a modification reaction under a preset reaction condition, carrying out solid-liquid separation on a reaction mixture after the modification reaction is finished to obtain modified biomass charcoal and waste liquid, dehydrating and washing the modified biomass charcoal, recycling the modifier in the modified biomass charcoal, and drying the modified biomass charcoal qualified in washing to obtain the heavy metal adsorbent. The method is efficient, energy-saving, environment-friendly and convenient to operate, reduces modification cost and reduces environmental pollution.

Inventors

  • ZENG DUO
  • LI JIE
  • YANG YUHANG
  • CUI YI
  • GUO CHEN
  • DING YUXIAO
  • WANG LELE
  • YU CHANGCHUN
  • LI ZHOU
  • BAO QIANG

Assignees

  • 华能重庆珞璜发电有限责任公司
  • 西安热工研究院有限公司

Dates

Publication Date
20260505
Application Date
20260403

Claims (10)

  1. 1. A method for preparing a heavy metal adsorbent by modifying biomass charcoal, which is characterized by comprising the following steps: selecting biomass charcoal raw materials, crushing, screening the crushed biomass charcoal raw materials, and drying the screened biomass charcoal raw materials; preparing a modifier solution with the concentration of 0.5mol/L to 1mol/L, and uniformly stirring the modifier solution; Mixing the modifier solution and the dried biomass charcoal raw material according to a preset mass ratio, uniformly stirring, and carrying out modification reaction under preset reaction conditions; after the modification reaction is finished, carrying out solid-liquid separation on the reaction mixture to obtain modified biomass charcoal and waste liquid; dehydrating and washing the modified biomass charcoal, and recycling the modifier in the modified biomass charcoal; and drying the qualified washed modified biomass charcoal to obtain the heavy metal adsorbent.
  2. 2. The method of claim 1, wherein the modifier solution comprises a hydrochloric acid-ferric chloride mixed modifier or a sulfuric acid-zinc chloride mixed modifier.
  3. 3. The method of claim 1, wherein mixing and stirring the modifier solution and the dried biomass charcoal raw material uniformly according to a preset mass ratio comprises: mixing the modifier solution with the dried biomass charcoal raw material according to the mass ratio of (3-5): 1.
  4. 4. The method of claim 1, wherein the modifier solution and the dried biomass charcoal raw material are mixed and stirred uniformly according to a preset mass ratio, further comprising: And stirring the modifier solution and the biomass charcoal raw material in a mode of combining ultrasonic vibration and mechanical stirring, controlling ultrasonic power to 250-300W and stirring rotation speed to 60-70 r/min, and ensuring that the biomass charcoal and the modifier are fully contacted and uniformly mixed.
  5. 5. The method according to claim 1, wherein the modification reaction is performed under preset reaction conditions, comprising: And (3) controlling the reaction temperature to be 50-60 ℃ by adopting a water bath temperature control mode, monitoring the pH value and the temperature of a reaction system in real time with the temperature control precision +/-2 ℃, and controlling the reaction time to be 30 min-60 min for modification reaction.
  6. 6. The method of claim 1, wherein the modified biomass char is dewatered and washed and the modifier in the modified biomass char is recovered for recycling, comprising: Carrying out filter pressing dehydration treatment on the modified biomass charcoal, and extruding out a residual modifier in the modified biomass charcoal; and washing the modified biomass carbon subjected to filter pressing and dehydration by adopting deionized water until the pH value of the washing liquid reaches 6.5-7.5, and collecting washing wastewater to recover the residual modifier.
  7. 7. The method of claim 1, wherein drying the washed-acceptable modified biomass char comprises: drying the qualified modified biomass charcoal by adopting a hot air circulation drying mode, and controlling the drying temperature to be 110 ℃ and the drying time to be 35 minutes.
  8. 8. The method of claim 1, wherein selecting the biomass charcoal raw material for pulverization, sieving the pulverized biomass charcoal raw material, and then drying the sieved biomass charcoal raw material, comprises: Pulverizing biomass charcoal raw material to particle size less than or equal to 0.1mm; Screening the crushed biomass charcoal raw material to remove impurities and unqualified particle size materials; and drying the sieved biomass charcoal raw material at the temperature of 100-110 ℃.
  9. 9. The method of claim 1, wherein after obtaining the heavy metal adsorbent, the method further comprises: The quality detection of the heavy metal adsorbent is carried out, so that the adsorption capacity of the heavy metal adsorbent to Cr 6+ is more than or equal to 150mg/g, and the adsorption capacity of the heavy metal adsorbent to Pb 2+ is more than or equal to 200mg/g.
  10. 10. A heavy metal adsorbent, characterized in that the heavy metal adsorbent is prepared by a method for preparing the high-efficiency heavy metal adsorbent by modifying biomass charcoal according to any one of claims 1 to 9.

Description

Method for preparing heavy metal adsorbent by modifying biomass charcoal and heavy metal adsorbent Technical Field The invention belongs to the technical field of preparation of heavy metal adsorbents, and particularly relates to a method for preparing a heavy metal adsorbent by modifying biomass charcoal and the heavy metal adsorbent. Background With the rapid development of industry, the discharge amount of heavy metal wastewater (such as wastewater containing Cr, pb, cd, cu and other heavy metal ions) is increased year by year, and the heavy metal ions have the characteristics of high toxicity, difficult degradation, easy accumulation and the like, and once entering water and soil, the heavy metal ions seriously threaten ecological environment and human health. Therefore, the treatment of heavy metal wastewater has become an important issue in the field of environmental protection. The adsorption method is one of the common methods for treating heavy metal wastewater, has the advantages of simple operation, high treatment efficiency, low cost, no secondary pollution and the like, and the performance of the adsorbent directly determines the adsorption treatment effect. The biomass charcoal is used as a novel adsorption material, has wide sources, low cost and good environmental compatibility, but the unmodified biomass charcoal has the advantages of small number of surface functional groups, low adsorption capacity and limited adsorption effect on heavy metal ions, and is difficult to meet the requirement of advanced treatment of high-concentration heavy metal wastewater. The surface structure of the biomass charcoal can be improved, the number of surface functional groups can be increased, and the adsorption capacity and the adsorption selectivity of the biomass charcoal to heavy metal ions can be improved through a physical, chemical or biological modification method. The chemical modification method is a mainstream method for modifying biomass charcoal because of remarkable modification effect, convenient operation and easy large-scale application. However, the existing biomass charcoal chemical modification technology generally has the problems of low modifier utilization rate, high energy consumption in the modification process, poor adsorption stability of modified biomass charcoal, easiness in secondary pollution caused by modified waste liquid and the like, and the industrialized application of the modified biomass charcoal chemical modification technology is limited. According to the technical scheme disclosed in the Chinese patent document CN114307957A, the adsorption performance of biomass charcoal can be improved to a certain extent by modifying and combining with hydrothermal carbonization to prepare the heavy metal ion adsorbent, but the method has the following defects that firstly, the modification mode is single, only dilute sulfuric acid is adopted for soaking and modifying, active sites on the surface of the biomass charcoal cannot be fully activated, and only partial biomass elements can be dissolved by dilute sulfuric acid, so that the improvement effect on the pore structure of the biomass charcoal is limited, the adsorption capacity of the prepared adsorbent is low, and the requirement of deep treatment of high-concentration heavy metal wastewater is difficult to meet; the method has the advantages of complex process, higher energy consumption, modification by dilute sulfuric acid, leaching and drying, 240 ℃ high-temperature hydrothermal carbonization for 2 hours, high energy consumption in the high-temperature hydrothermal process, further increased energy consumption in the multi-step drying treatment, adverse to large-scale energy-saving production, extremely low utilization rate of the modifier, no recycling link, discharge of a large amount of dilute sulfuric acid along with leaching wastewater, production cost increase, secondary pollution caused by acidic wastewater, poor environmental friendliness, unreasonable leaching and washing flow, leaching to neutrality by only adopting deionized water, and orderly washing by hydrochloric acid solution and deionized water, consumption of a large amount of water resources, incapacity of thoroughly removing residual dilute sulfuric acid and impurities on the surface of biomass charcoal, influence on the adsorption stability of the adsorbent due to residual acidic substances, and possible secondary acidification of water, lack of accurate parameter regulation mechanism, undefined dilute sulfuric acid concentration, soaking time, accurate parameter range of hydrothermal carbonization, uneven quality of the adsorbent due to parameter fluctuation, poor adsorption effect stability, and no treatment on the leaching wastewater, the acid-containing wastewater generated in the flushing process is directly discharged, so that the environmental pollution is further aggravated, and the environment-friendly production requirement is not met. In summ