A foam separation method for harvesting Cr 3+ Method
By using Sapindus mukorossi extract as a foaming agent and trapping agent, and controlling the foam separation process conditions, the problem of separating and harvesting low-concentration Cr3+ aqueous solutions was solved, achieving efficient and economical Cr3+ separation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAMEN UNIV
- Filing Date
- 2026-04-02
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies are difficult to process low-concentration Cr3+ aqueous solutions efficiently and economically, and suffer from problems such as complex processes, high operating costs, and unsatisfactory separation and enrichment efficiency.
Sapindus mukorossi extract was used as a natural nonionic surfactant, serving as both a foaming agent and a collector, to separate foam from aqueous solutions containing Cr3+. By controlling process conditions such as pH, gas flow rate, and collection time, Cr3+ was enriched in the foam phase and harvested.
It achieves efficient separation and harvesting of low-concentration Cr3+ with a recovery rate of 71.5% and an enrichment ratio of 3.9. The equipment is simple, energy-efficient, and environmentally friendly.
Smart Images
Figure CN122303634A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heavy metal wastewater treatment technology, and particularly to a method for foam separation and harvesting of Cr. 3+ The method. Background Technology
[0002] Chromium is one of the most common heavy metal elements in the environment, usually in the form of Cr. 3+ and Cr 6+ Two valence states exist. Cr 6+ It is highly toxic, while Cr 3+ Although its toxicity is relatively low, when its concentration in water is too high, it can still have adverse effects on humans, animals, and plants. Therefore, Cr-containing substances... 3+ Wastewater still needs to be effectively treated.
[0003] Existing methods for treating wastewater containing heavy metals mainly include physical adsorption, chemical precipitation, flocculation, ion exchange, and biological methods. These methods are effective for treating high-concentration systems, but less so for low-concentration Cr... 3+ Aqueous solutions often suffer from problems such as complex processes, high operating costs, and unsatisfactory separation and enrichment efficiency.
[0004] Therefore, a foam separation method for harvesting Cr is being developed. 3+ This technology has significant practical implications and promising application prospects. Summary of the Invention
[0005] The purpose of this invention is to solve the problem of low concentration Cr in the prior art. 3+ To address the aforementioned problems of inefficient and economical separation and harvesting of Cr from aqueous solutions, a foam separation and harvesting method is provided. 3+ The method uses Sapindus mukorossi extract, a natural nonionic surfactant, as a foaming agent and a trapping agent to target Cr-containing compounds. 3+ Foam separation was performed using an aqueous solution to separate Cr. 3+ Enriched in the foam phase and harvested.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A foam separation method for harvesting Cr 3+ The method uses Sapindus mukorossi extract as a foaming agent and a trapping agent to target Cr-containing compounds. 3+ Foam separation was performed using an aqueous solution of Sapindus mukorossi extract, and the concentration of Cr was controlled within the aqueous solution. 3+ The mass concentration of the aqueous solution is 0.15~0.25 g / L, the pH of the aqueous solution is controlled at 5.5~6.5, and the flow rate of the introduced gas is controlled at 380~420 mL / min, so that Cr 3+ Enrichment in the foam phase, collection of the foam phase, and realization of Cr 3+ Harvesting.
[0008] In the foam separation process conditions, the pH is 6.5.
[0009] In the process conditions for foam separation, the gas flow rate is 400 mL / min.
[0010] In the foam separation process conditions, the mass concentration of Sapindus mukorossi extract is 0.2 g / L.
[0011] The time for collecting the foam phase is 2 to 6 minutes.
[0012] Preferably, the time for collecting the foam phase is 4 minutes.
[0013] The Cr-containing 3+ The loading capacity of the aqueous solution is 100~500 mL.
[0014] Preferably, the Cr-containing 3+ The volume of the aqueous solution is 300 mL.
[0015] The Cr-containing 3+ In aqueous solution, Cr 3+ The mass concentration is 5~25 mg / L, preferably 10 mg / L.
[0016] The Sapindus mukorossi extract is a natural nonionic surfactant with a critical micelle concentration of 0.5 g / L.
[0017] The Cr-containing 3+ The aqueous solution is industrial wastewater, experimental simulated wastewater, or Cr-containing solution prepared from chromium sulfate. 3+ Aqueous solution.
[0018] Compared with the prior art, the beneficial effects achieved by the technical solution of this invention are:
[0019] This invention employs foam separation, a novel separation method based on the adsorption differences at the gas-liquid interface to achieve the separation and enrichment of target components. It has advantages such as low energy consumption, simple equipment, and good separation effect on low concentration systems, and is suitable for the separation and harvesting of trace components in water.
[0020] This invention utilizes Sapindus mukorossi extract as a natural nonionic surfactant. It is widely available, possesses strong surface activity and good foaming properties, and is also readily degradable and environmentally friendly. Applying it to the foam separation process can reduce the burden of chemical reagents while achieving the separation of low concentrations of Cr. 3+ Effective separation and harvesting.
[0021] The Sapindus mukorossi extract of this invention has both foaming and trapping effects, which can reduce the types of added agents. It is also naturally derived, easily degradable, low in toxicity, and environmentally friendly. Under optimized process conditions, Cr...3+ The recovery rate can reach 71.5%, and the enrichment ratio is 3.9, making it suitable for low-concentration Cr. 3+ Separate harvesting of the system. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the foam separation device used in this invention.
[0023] Figure 2 pH value for Cr 3+ The effect of recovery rate and enrichment ratio.
[0024] Figure 3 Gas flow rate versus Cr 3+ The effect of recovery rate and enrichment ratio.
[0025] Figure 4 For the collection time of Cr 3+ The effect of recovery rate and enrichment ratio.
[0026] Figure 5 For the load on Cr 3+ The effect of recovery rate and enrichment ratio.
[0027] Figure 6 The effect of Sapindus mukorossi extract concentration on Cr 3+ The effect of recovery rate and enrichment ratio.
[0028] Figure 7 The effect of chromium sulfate concentration on Cr 3+ The effect of recovery rate and enrichment ratio. Detailed Implementation
[0029] To make the technical problems, technical solutions and beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0030] In this invention, the main materials used in the experiment include Sapindus mukorossi extract, chromium sulfate, sodium hydroxide, and hydrochloric acid; the main instruments include a surface tension meter, an atomic absorption spectrophotometer, a pH meter, a rotor flow meter, and a foam separation device. This invention determines the critical micelle concentration of Sapindus mukorossi extract and other surfactants using the surface tension method, and employs single-factor experiments to investigate the effects of pH, gas flow rate, collection time, liquid loading, Sapindus mukorossi extract concentration, and chromium source concentration on the foam separation effect. Finally, a three-factor, three-level orthogonal experiment is used to optimize the process conditions.
[0031] See Figure 1The foam separation device used in this invention includes an air compressor bottle 1, a pressure reducing valve 2, a pressure gauge 3, a regulating valve 4, a rotor flow meter 5, a shut-off valve 6, a regulating valve 7, a foam generating tube 8, an iron frame 9, a collection bottle 10, and a lifting platform 11. In use, gas, after flow regulation, enters the bottom of the foam generating tube, forming bubbles in the liquid phase and rising. The foam overflows from the top of the column and enters the collection bottle, achieving the enrichment of the target component in the foam phase.
[0032] The critical micelle concentrations (CMCs) of six surfactants were determined using the surface tension method. The results showed that the CMCs of SDS, DBS, SDBS, CTAB, CAPB, and Sapindus mukorossi extract were 1.2 g / L, 1.5 g / L, 0.4 g / L, 1.9 g / L, 0.2 g / L, and 0.5 g / L, respectively. Sapindus mukorossi extract, while possessing a natural source and environmental friendliness, exhibits suitable surface activity and can be used in foam separation systems.
[0033] In this invention, Cr 3+ The separation effect is evaluated using recovery rate and enrichment ratio, and the calculation formulas are as follows:
[0034] Recovery rate: R (%) = C f V f / (C0V0)×100%;
[0035] Enrichment ratio: E = C f / C0;
[0036] Among them, C0 and C f Cr in the raw material solution and the extracted foam solution, respectively 3+ The concentrations, V0 and V f These represent the volumes of the raw material liquid and the extracted foam liquid after foam breakage, respectively.
[0037] The Cr content in the collected liquid was determined using an atomic absorption spectrophotometer. 3+ Concentration, obtained by calculation of Cr 3+ Recovery rate and enrichment ratio.
[0038] Example 1: The effect of pH value on the foam separation and harvesting of Cr 3+ Impact
[0039] A mixed solution with a chromium sulfate concentration of 10 mg / L and a Sapindus mukorossi extract concentration of 0.2 g / L was prepared. The pH was adjusted to 2, 4, 6, 8 and 10, respectively. The loading volume was fixed at 100 mL, the collection time was 4 min, and the gas flow rate was 400 mL / min for the experiment.
[0040] Figure 2 The results showed that Cr 3+The recovery rate initially increased and then decreased with increasing pH, reaching a relatively high level at pH 6; the enrichment ratio initially increased and then decreased with increasing pH, showing little change within the pH range of 6–8. Considering all factors, pH 6 is the optimal pH under single-factor conditions.
[0041] Example 2: Effect of gas flow rate on foam separation and Cr harvesting 3+ Impact
[0042] A mixed solution with a chromium sulfate concentration of 10 mg / L and a Sapindus mukorossi extract concentration of 0.2 g / L was prepared. The pH was adjusted to 6, the liquid volume was 200 mL, and the collection time was 4 min. The gas flow rate was adjusted to 200, 300, 400, 500 and 600 mL / min for the experiment.
[0043] Figure 3 The results show that as the gas flow rate increases, Cr 3+ Recovery initially increases and then decreases, reaching an optimal level at a gas flow rate of 400 mL / min. The enrichment ratio shows a generally consistent trend, therefore, under single-factor conditions, the suitable gas flow rate is 400 mL / min.
[0044] Example 3: Effect of collection time on foam separation and Cr harvesting 3+ Impact
[0045] In this invention, the collection time refers to the duration from when the foam begins to overflow from the top of the tower until the collection stops.
[0046] A mixed solution with a chromium sulfate concentration of 10 mg / L and a Sapindus mukorossi extract concentration of 0.2 g / L was prepared. The pH was adjusted to 6, the liquid loading volume was 200 mL, and the gas flow rate was 400 mL / min. The foam liquid was collected starting from the top of the column, and the collection time was 2, 3, 4, 5 and 6 min respectively.
[0047] Figure 4 The results showed that the enrichment ratio was highest when the collection time was 4 min, while the recovery rate did not change significantly after 4 min. Considering both energy consumption and separation efficiency, the optimal collection time was 4 min.
[0048] Example 4: Effect of liquid loading on foam separation and harvesting of Cr 3+ Impact
[0049] A mixed solution with a chromium sulfate concentration of 10 mg / L and a Sapindus mukorossi extract concentration of 0.2 g / L was prepared. The pH was adjusted to 6, the gas flow rate was 400 mL / min, the collection time was 4 min, and the liquid loading volumes were 100, 200, 300, 400 and 500 mL, respectively.
[0050] Figure 5The results showed that Cr 3+ The recovery rate and enrichment ratio both increased first and then decreased with increasing liquid loading. The separation effect was better when the liquid loading was 300 mL, so the appropriate liquid loading was 300 mL.
[0051] Example 5: Effect of Sapindus mukorossi extract concentration on Cr content during foam separation and harvesting 3+ Impact
[0052] Prepare a mixed solution with a chromium sulfate concentration of 10 mg / L. Set the concentrations of Sapindus mukorossi extract to 0.10, 0.15, 0.20, 0.25 and 0.30 g / L, respectively. Adjust the pH to 6, the gas flow rate to 400 mL / min, the collection time to 4 min, and the liquid loading volume to 300 mL.
[0053] Figure 6 The results showed that Cr 3+ The recovery rate first increased and then decreased with increasing concentration of Sapindus mukorossi extract, reaching its highest value at a concentration of 0.2 g / L. The enrichment ratio was also at an optimal level under these conditions, therefore the suitable concentration of Sapindus mukorossi extract is 0.2 g / L.
[0054] Example 6: Effect of chromium sulfate concentration on foam separation and Cr harvesting 3+ Impact
[0055] A mixed solution of Sapindus mukorossi extract with a mass concentration of 0.2 g / L was prepared, and chromium sulfate with mass concentrations of 5, 10, 15, 20 and 25 mg / L was prepared. The pH was adjusted to 6, the gas flow rate was 400 mL / min, the collection time was 4 min, and the liquid loading volume was 300 mL.
[0056] Figure 7 The results showed that Cr 3+ The recovery rate first increased and then decreased with increasing chromium sulfate concentration, reaching a relatively high level at a chromium sulfate mass concentration of 10 mg / L; the enrichment ratio also performed well near this concentration, therefore the suitable chromium sulfate mass concentration is 10 mg / L.
[0057] Example 7: Optimization of Orthogonal Experiment
[0058] Based on the results of the single-factor experiments, the concentration of Sapindus mukorossi extract, gas flow rate, and pH value were selected as the factors to be investigated, and a three-factor, three-level orthogonal experiment was conducted as shown in Table 1. Where A represents the concentration of Sapindus mukorossi extract, B represents the gas flow rate, and C represents the pH value.
[0059] Table 1
[0060]
[0061] Table 1 shows the results of the orthogonal experiment, R A>R B >R C Various factors affecting the foam separation and harvesting of Cr 3+ The order of influence is: Sapindus mukorossi extract concentration > gas flow rate > pH value.
[0062] Based on the K value, it can be seen that foam separation and harvesting of Cr 3+ The optimal process conditions are: pH 6.5, gas flow rate 400 mL / min, collection time 4 min, loading volume 300 mL, Sapindus mukorossi extract concentration 0.2 g / L, and chromium sulfate concentration 10 mg / L. Under these conditions, Cr 3+ The recovery rate reached 71.5%, and the enrichment ratio was 3.9.
[0063] This invention uses Sapindus mukorossi extract as a natural nonionic surfactant in foam separation methods to remove trace amounts of Cr in aqueous solutions. 3+ Separation and harvesting were carried out. Single-factor experiments showed that the optimal conditions were: pH 6, gas flow rate 400 mL / min, collection time 4 min, liquid volume 300 mL, Sapindus mukorossi extract concentration 0.2 g / L, and chromium sulfate concentration 10 mg / L. Under these conditions, the recovery rate was 70.2%, and the enrichment ratio was 3.8. Further, a three-factor, three-level orthogonal experiment was designed. Finally, the optimal conditions were determined to be: pH 6.5, gas flow rate 400 mL / min, collection time 4 min, liquid volume 300 mL, Sapindus mukorossi extract concentration 0.2 g / L, and chromium sulfate concentration 10 mg / L. At this point, the Cr... 3+ The recovery rate reached 71.5%, and the enrichment ratio was 3.9. The method of this invention is characterized by its simple process, environmental friendliness, and suitability for treating low-concentration systems.
Claims
1. A foam separation method for harvesting Cr 3+ The method is characterized by: Using Sapindus mukorossi extract as a foaming agent and trapping agent, for Cr-containing 3+ Foam separation was performed using an aqueous solution of Sapindus mukorossi extract, and the concentration of Cr was controlled within the aqueous solution. 3+ The mass concentration of the aqueous solution is 0.15~0.25 g / L, the pH of the aqueous solution is controlled at 5.5~6.5, and the flow rate of the introduced gas is controlled at 380~420 mL / min, so that Cr 3+ Enrichment in the foam phase, collection of the foam phase, and realization of Cr 3+ Harvesting.
2. The foam separation and harvesting method for Cr as described in claim 1 3+ The method is characterized by: In the foam separation process conditions, the pH is 6.
5.
3. A foam separation and harvesting method for Cr as described in claim 1 3+ The method is characterized by: In the process conditions for foam separation, the gas flow rate is 400 mL / min.
4. A foam separation and harvesting method for Cr as described in claim 1 3+ The method is characterized by: In the foam separation process conditions, the mass concentration of Sapindus mukorossi extract is 0.2 g / L.
5. A foam separation and harvesting method for Cr as described in claim 1 3+ The method is characterized by: The time for collecting the foam phase is 2 to 6 minutes.
6. A foam separation and harvesting method for Cr as described in claim 5 3+ The method is characterized by: The time for collecting the foam phase is 4 minutes.
7. A foam separation and harvesting method for Cr as described in claim 1 3+ The method is characterized by: The Cr-containing 3+ The loading capacity of the aqueous solution is 100~500 mL.
8. A foam separation and harvesting method for Cr as described in claim 7 3+ The method is characterized by: The Cr-containing 3+ The volume of the aqueous solution is 300 mL.
9. A foam separation and harvesting method for Cr as described in claim 1 3+ The method is characterized by: The Cr-containing 3+ In aqueous solution, Cr 3+ The mass concentration is 5~25 mg / L, preferably 10 mg / L.
10. A foam separation and harvesting method for Cr as described in claim 1 3+ The method is characterized by: The Sapindus mukorossi extract is a natural nonionic surfactant with a critical micelle concentration of 0.5 g / L.