Method for detecting trace gold ions in wastewater
By preparing polyurethane microspheres combined with PAMAM solid powder, the accuracy and complexity problems of trace gold ion detection were solved, and a simple and low-cost trace gold ion detection method was realized, which is suitable for the accurate determination of trace gold ions in wastewater.
Patent Information
- Application Number
- CN202510738316.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-04
- Publication Date
- 2025-10-03
AI Technical Summary
Existing technologies have difficulty in accurately detecting trace gold ions in wastewater, especially when mixed metal ions are present. The detection accuracy is not ideal, and the operation is complicated and the cost is high.
Polyurethane microspheres are prepared by combining PAMAM solid powder with polyurethane microspheres. The highly selective adsorption ability of PAMAM is used to separate trace gold ions, and the gold ion concentration is determined by weight difference. Precise calculation steps are combined to ensure the accuracy of the detection.
A simple and low-cost trace gold ion detection is achieved with high accuracy and reliability, which is suitable for practical applications and reduces detection complexity and equipment cost.
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of trace analysis, in particular to a method for detecting trace gold ions in wastewater. Background Art
[0002] Trace analysis is a technique for analyzing and measuring extremely low concentrations of components in a sample. It plays a vital role in fields such as environmental science, biology, medicine, and materials science. For metal ions in wastewater, trace analysis can accurately detect their presence and concentration, which is crucial for assessing water pollution levels, monitoring environmental changes, and developing environmental protection measures. Through trace analysis, we can promptly identify potentially harmful substances in wastewater, enabling us to take measures to reduce their impact on the environment and human health.
[0003] In sewage and wastewater, metal ions are a serious pollutant that can cause serious harm to the environment and animals and plants. There are mature technologies for removing metal ions in sewage and wastewater, but there are inevitably some residuals. The concentration of the residual trace metal ions can be determined by trace analysis, but the accuracy of trace detection of a certain metal ion is not ideal. Due to the interference of other metal ions, trace detection of a single metal ion often requires a highly selective marker, and it is also necessary to accurately prepare a dilute solution of the marker. The recovery and detection of the reactants also requires high processing accuracy. Any error in each step of the operation will lead to detection failure. Therefore, there is a need for a trace detection method for a certain metal ion in a mixed metal ion that is not difficult. Summary of the Invention
[0004] In view of the difficulty in the existing trace analysis of a specific metal ion in water, the present invention provides a method for detecting trace gold ions in wastewater, comprising the following steps: 1. Preparation of PAMAM solid powder PAMAM is added to an organic solvent, an isocyanate compound and an organotin catalyst are added, and a polyether polyol and a dispersant are added dropwise under heating and stirring until the precipitate no longer increases and the reaction is terminated. The precipitate is filtered and fully dehydrated, crushed and sieved to obtain a PAMAM solid powder; 2. Concentration Accurately measure the treated wastewater and slowly concentrate it to the required weight under low temperature and low pressure; 3. Adsorption Accurately weigh a certain weight of the PAMAM solid powder obtained in step 1, add it to the concentrated solution obtained in step 2, heat and stir, then filter, and fully dehydrate the filtrate; 4. Calculation The concentration of trace gold ions in the wastewater was obtained by subtracting the mass of the PAMAM solid powder before adsorption from the mass of the dehydrated PAMAM solid powder after adsorption.
[0005] PAMAM, a dendrimer material, exhibits 100% selective adsorption for Au(III) and is virtually unaffected by other metal ions when multiple ions coexist. It exhibits advantages for Au(III), including high adsorption efficiency, a low adsorption concentration threshold, and strong adsorption durability. However, PAMAM is a liquid, making it suitable for purifying higher-concentration wastewater, but inadequate for the determination of trace gold ions. Based on this, the present invention combines PAMAM with polyurethane to produce polyurethane microspheres containing PAMAM. The PAMAM on the microsphere surface retains its adsorption capacity for trivalent gold ions, thereby separating trace gold ions from wastewater. The weight difference of the polyurethane microspheres is then used to determine the weight of the adsorbed gold element, thereby determining the concentration of trace gold ions in the wastewater.
[0006] Furthermore, the present invention ensures accurate determination of trace gold ion concentrations through precise calculation steps. After the adsorption step, the dehydrated PAMAM solid powder is accurately weighed and compared to its weight before adsorption. This difference directly reflects the mass of the adsorbed gold ions. Since the wastewater treatment, concentration, adsorption, and final calculations are strictly controlled throughout the entire process, the method provided by the present invention has high accuracy and reliability and is suitable for the precise detection of trace gold ions in wastewater.
[0007] The detection method of the present invention does not require complex and precise operations. After preparing the PAMAM solid powder, the wastewater is concentrated to increase the adsorption effect. The weighing accuracy can be simply determined based on the data range of the total weight, and the concentration of trace gold ions in the wastewater can be obtained after a simple calculation. At the same time, the method is simple to operate and does not require expensive equipment and complex pretreatment steps, which greatly reduces the cost of detection. In addition, due to the stability and reusability of the polyurethane microspheres, the method has high cost and practicality in practical applications, providing a new approach for the detection of trace gold ions in wastewater.
[0008] Furthermore, in step 1 of the method of the present invention, the PAMAM is second-generation PAMAM or third-generation PAMAM; the isocyanate compound is one of MDI, HDI, TDI, or a polyurethane prepolymer with a molecular weight of 10,000 to 30,000; the dispersant is a Solsperse dispersant or a Hypermer dispersant; the PAMAM solid powder is sieved to a fineness of 10 to 100 μm; the heating temperature is 50 to 70°C, and the stirring speed is 300 to 500 rpm. In step 2, the low temperature is 50 to 70°C, and the low pressure is 500 to 1000 Pa. In step 3, the heating temperature is 30 to 50°C, and the stirring speed is 100 to 300 rpm. DETAILED DESCRIPTION
[0009] The present invention is described below with reference to examples, which are only used to explain the present invention and are not used to limit the scope of the present invention.
[0010] Example 1 A method for detecting trace trivalent gold ions in wastewater comprises the following steps: 1. Add 100 parts by weight of the third-generation PAMAM to 50 parts by weight of DMSO, add 100 parts by weight of MDI and 15 parts by weight of DBTDL, and add dropwise 50 parts by weight of propylene glycol polyether with a molecular weight of 800 and 30 parts by weight of Solsperse dispersant at 65°C and 400 rpm under stirring until the precipitate no longer increases and the reaction is terminated. The precipitate is filtered and fully dehydrated, crushed and sieved to 20 μm to obtain a PAMAM solid powder; 2. Accurately measure 1kg of treated wastewater and slowly concentrate it to 500g at 60℃ and 600Pa; 3. Accurately weigh 10.000 g of the PAMAM solid powder obtained in step 1 and add it to the concentrated solution obtained in step 2. Stir at 40°C and 200 rpm for 24 hours, then let it stand for 18 hours, filter, and fully dehydrate the filtrate. 4. The mass of the dehydrated PAMAM solid powder after adsorption was weighed to be 10.053 g, and the adsorption amount was 0.053 g, so the concentration of gold ions was 53 ppm.
[0011] The gold ion content in the wastewater of this embodiment was measured by inductively coupled plasma atomic emission spectrometry and was 54.3 ppm. The error measured by the method of this embodiment was 2.45%.
[0012] Example 2 A method for detecting trace trivalent gold ions in wastewater comprises the following steps: 1. Add 100 parts by weight of the second-generation PAMAM to 30 parts by weight of DMAc, add 80 parts by weight of HDI and 10 parts by weight of stannous octoate, and add 40 parts by weight of PPG1000 and 20 parts by weight of Hypermer dispersant dropwise at 55°C and 500 rpm with stirring until the precipitate no longer increases and the reaction is terminated. The precipitate is filtered and fully dehydrated, crushed and sieved to 30 μm to obtain a PAMAM solid powder; 2. Accurately measure 1kg of treated wastewater and slowly concentrate it to 500g at 70℃ and 100Pa; 3. Accurately weigh 10.000 g of the PAMAM solid powder obtained in step 1 and add it to the concentrated solution obtained in step 2. Stir at 30°C and 300 rpm for 24 hours, then let it stand for 12 hours, filter, and fully dehydrate the filtrate. 4. The mass of the dehydrated PAMAM solid powder after adsorption was weighed to be 10.078 g, and the adsorption amount was 0.078 g, so the concentration of gold ions was 78 ppm.
[0013] The gold ion content in the wastewater of this embodiment was measured by inductively coupled plasma atomic emission spectrometry and was found to be 80.2 ppm. The error measured by the method of this embodiment was 2.82%.
[0014] Example 3 A method for detecting trace trivalent gold ions in wastewater comprises the following steps: 1. Add 100 parts by weight of the third-generation PAMAM to 60 parts by weight of DMF, add 120 parts by weight of 20000 polyurethane prepolymer and 8 parts by weight of DBTDL, and add 80 parts by weight of polyether polyol n330 and 60 parts by weight of Solsperse dispersant dropwise at 55°C and 300 rpm with stirring until the precipitate no longer increases and the reaction is terminated. The precipitate is filtered and fully dehydrated, crushed and sieved to 100 μm to obtain PAMAM solid powder; 2. Accurately measure 1kg of treated wastewater and slowly concentrate it to 500g at 50℃ and 300Pa; 3. Accurately weigh 10.000 g of the PAMAM solid powder obtained in step 1 and add it to the concentrated solution obtained in step 2. Stir at 50°C and 100 rpm for 24 hours, then let it stand for 6 hours, filter, and fully dehydrate the filtrate. 4. The mass of the dehydrated PAMAM solid powder after adsorption was weighed to be 10.124 g, and the adsorption amount was 0.124 g, so the concentration of gold ions was 124 ppm.
[0015] The gold ion content in the wastewater of this embodiment was measured by inductively coupled plasma atomic emission spectrometry and was found to be 119 ppm. The error measured by the method of this embodiment was 4%.
[0016] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A method for detecting trace gold ions in wastewater, characterized in that: The following steps are involved:
1. Preparation of PAMAM solid powder PAMAM is added to an organic solvent, an isocyanate compound and an organotin catalyst are added, and a polyether polyol and a dispersant are added dropwise under heating and stirring until the precipitate no longer increases and the reaction is terminated. The precipitate is filtered and fully dehydrated, crushed and sieved to obtain a PAMAM solid powder; 2. Concentration Accurately measure the treated wastewater and slowly concentrate it to the required weight under low temperature and low pressure; 3. Adsorption Accurately weigh a certain weight of the PAMAM solid powder obtained in step 1, add it to the concentrated solution obtained in step 2, heat and stir, then filter, and fully dehydrate the filtrate; 4. Calculation The concentration of trace gold ions in the wastewater was obtained by subtracting the mass of the PAMAM solid powder before adsorption from the mass of the dehydrated PAMAM solid powder after adsorption.
2. The method according to claim 1, characterized in that The gold ions are trivalent gold ions.
3. The method according to claim 2, characterized in that In step 1, the PAMAM is a second-generation PAMAM or a third-generation PAMAM.
4. The method according to claim 2, characterized in that In step 1, the organic solvent is one of DMSO, DMAc or DMF.
5. The method according to claim 2, characterized in that In step 1, the isocyanate compound is one of MDI, HDI, TDI or a polyurethane prepolymer with a molecular weight of 10,000 to 30,000.
6. The method according to claim 2, characterized in that In step 1, the dispersant is a Solsperse dispersant or a Hypermer dispersant.
7. The method according to claim 2, characterized in that In step 1, the screening fineness is 10~100μm.
8. The method according to claim 2, characterized in that In step 1, the heating temperature is 50-70°C and the stirring speed is 300-500 rpm.
9. The method according to claim 2, characterized in that In step 2, the low temperature is 50-70°C and the low pressure is 500-1000Pa.
10. The method according to claim 2, characterized in that In step 3, the heating temperature is 30-50°C and the stirring speed is 100-300 rpm.