A method for adsorbing heavy metal vanadium in beneficiation wastewater

Abstract

The present application relates to a kind of methods for adsorbing heavy metal vanadium in beneficiation wastewater, belong to wastewater treatment technical field, specifically including using hydrothermal method synthesis zinc-doped nickel iron hydrotalcite;Vanadium in water is removed by zinc-doped nickel iron hydrotalcite under neutral condition, and adsorption time is 0.25-24 hours, and temperature is room temperature;The present application can effectively reduce energy consumption and the use of chemical substances, reduce the treatment cost, and the adsorption rate is high.

Description

Technical Field

[0001] This invention relates to a method for adsorbing heavy metal vanadium from mineral processing wastewater, belonging to the field of wastewater treatment technology. Background Technology

[0002] Vanadium exists naturally in 65 different minerals and is also found in fossil fuels. Its excellent properties have led to its widespread application in many industries. Vanadium pentoxide and other oxides have shown significant industrial applications as suitable catalysts for sulfuric acid production and selective catalytic reactions. Furthermore, the application of vanadium redox flow batteries is a hot topic in hydrometallurgy. Therefore, vanadium recovery has broad development prospects. However, wastewater from metal ore beneficiation is one of the main sources of heavy metal pollution, typically containing heavy metal ions such as vanadium, mercury, cadmium, arsenic, lead, copper, and zinc. These heavy metal ions in beneficiation wastewater are currently identified as highly hazardous heavy metal elements. They are very stable in the environment, difficult to decompose and remove, and can only transform spatially or in terms of valence form; they easily accumulate in organisms, and once a certain concentration is reached, they will affect normal human metabolism, leading to various diseases. Vanadium, in particular, has received considerable attention due to its unique physical and chemical properties. The most common oxidation states in aqueous solutions are +3, +4, and +5, with V5+ being the most toxic. The main harms of vanadium to the human body are as follows: (1) Toxicity: Vanadium can cause acute and chronic toxicity to the human body. Acute poisoning symptoms include difficulty breathing, cough, chest pain, gastrointestinal discomfort, etc.; chronic poisoning is mainly manifested as bone and muscle pain, arthritis, skin damage, etc. (2) Respiratory system damage: After the dust or vapor of vanadium enters the human respiratory tract, it can cause respiratory irritation and inflammatory reactions, leading to respiratory diseases such as cough, wheezing, and bronchitis. (3) Nervous system damage: Vanadium can enter the human body through the blood and nervous system, causing damage to the central nervous system, leading to symptoms such as headache, dizziness, and neurasthenia. Therefore, mineral processing wastewater must be treated before discharge to meet discharge standards and minimize environmental harm.

[0003] Currently, commonly used methods for treating heavy metal vanadium pollution in mineral processing wastewater include chemical precipitation, adsorption, ion exchange, and membrane separation. Adsorption is widely recognized for its advantages such as strong adsorption capacity, high adsorption efficiency, low cost, and simple operation procedures. However, selecting the appropriate adsorbent for the specific target is crucial. Layered double hydroxides (LDHs) can also be described as hydrotalcite compounds. The general chemical formula of hydrotalcite is [(M... 2+ ) 1-x (M 3+ ) x (OH)2] x+ [A m- ]x / m ·nH₂O, LDHs have an octahedral structure, M 2+ M 3+ The symbols Am- and Am- represent divalent and trivalent cations, respectively, while Am- represents the interlayer anion, indicating the presence of numerous water molecules in the interlayer. This structural characteristic endows hydrotalcite with high adsorption capacity and selectivity, making it suitable for adsorbing and removing organic pollutants, heavy metal ions, and inorganic ions from water. By controlling the structure and composition of hydrotalcite, its adsorption properties can be altered, making it more suitable for specific adsorption applications. Therefore, in-depth research into the adsorption properties and control mechanisms of hydrotalcite will contribute to the development of highly efficient adsorption materials, enabling more effective water resource management and environmental protection. Hydrotalcite has broad application prospects in environmental pollution control, wastewater treatment, and water quality improvement. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a method for adsorbing heavy metal vanadium from mineral processing wastewater that can effectively reduce energy consumption and the use of chemicals, lower treatment costs, and has a high adsorption rate.

[0005] To achieve the above objectives, the technical solution adopted in this invention is a method for adsorbing heavy metal vanadium from mineral processing wastewater, the steps of which are as follows:

[0006] S1. Zinc-doped nickel-iron hydrotalcite was synthesized using a hydrothermal method;

[0007] S2. Zinc-doped nickel-iron hydrotalcite is used to adsorb and remove vanadium from water under neutral conditions. The adsorption time is 0.25-24 hours and the temperature is room temperature.

[0008] Preferably, the preparation method of zinc-doped nickel-iron hydrotalcite in step S1 is as follows: weigh a certain amount of Ni(NO3)2·6H2O, Fe(NO3)3·9H2O, Zn(NO3)2·6H2O, CH4N2O, and NH4F, disperse them in ultrapure water, stir for one hour to achieve uniform dispersion, and then transfer them to a stainless steel reactor. The clean nickel foam is immersed in the reactor at room temperature, and then the temperature of the high-pressure reactor is raised to 120°C and maintained for 12 hours. After cooling, the yellow nickel foam board containing the precursor is taken out, washed several times with water and ethanol, and dried in a vacuum drying oven at 60°C for 6 hours, which is denoted as NiFeZn-LDHs / NF.

[0009] Preferably, the molar ratio of Ni(NO3)2·6H2O to Fe(NO3)3·9H2O is 1:1.

[0010] Compared with the prior art, the present invention has the following technical effects:

[0011] 1) This invention utilizes the synergistic effect between three metals to effectively improve the adsorption performance of hydrotalcite, resulting in a significant increase in the adsorption effect of hydrotalcite on vanadium, with an adsorption rate as high as 94%. At the same time, it can avoid the use of chemical agents or energy-intensive physical treatment methods, thereby reducing energy consumption and the use of chemicals, and lowering the treatment cost.

[0012] 2) This invention uses a hydrothermal method to prepare hydrotalcite, eliminating the need for calcination, simplifying the process, and effectively reducing economic costs. Calcination requires high temperatures and thus a large energy supply, while hydrothermal methods typically operate at lower temperatures, resulting in lower energy consumption. The cost of producing modified nickel-iron hydrotalcite using the hydrothermal method can reach 154,500 yuan / ton, while the cost of producing modified nickel-iron hydrotalcite using the calcination method can reach 266,900 yuan / ton. The cost of producing modified nickel-iron hydrotalcite using the calcination method is 1.73 times that of synthesizing modified nickel-iron hydrotalcite using the hydrothermal method. Therefore, the hydrothermal method may be more economical and efficient. Attached Figure Description

[0013] Figure 1 This is a graph showing the equilibrium adsorption capacity of vanadium, a heavy metal in mineral processing wastewater, according to the present invention.

[0014] Figure 2 This is a graph showing the adsorption efficiency of the heavy metal vanadium in mineral processing wastewater according to the present invention.

[0015] Figure 3 The image shows the XRD pattern of the zinc-doped nickel-iron hydrotalcite prepared in this invention. Detailed Implementation

[0016] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0017] A method for adsorbing vanadium, a heavy metal, from mineral processing wastewater includes the following steps.

[0018] S1. Zinc-doped nickel-iron hydrotalcite was synthesized by hydrothermal method, and zinc-doped nickel-iron hydrotalcite was used as an adsorbent.

[0019] S2. Zinc-doped nickel-iron hydrotalcite is used to adsorb and remove vanadium from water under neutral conditions. The adsorption time is 0.25-24 hours, the pH value is 7, and the temperature is room temperature.

[0020] The initial concentration of vanadium in the wastewater was 200-2000 mg / L. The amount of adsorbent could be adjusted according to specific conditions, with an adsorbent-to-solution mass ratio of 1:100-200. The adsorption effect decreased as the initial vanadium concentration gradually increased. The adsorption time was 0.25-24 h, and the adsorption effect increased with time. After 10 h of adsorption, the adsorption basically reached equilibrium.

[0021] The preparation method of zinc-doped nickel-iron hydrotalcite is as follows: Ni(NO3)2·6H2O and Fe(NO3)3·9H2O are used as nickel and iron sources, respectively, and Zn(NO3)2·6H2O is used as the zinc source. CH4N2O is added to provide an alkaline environment, NH4F is used as a slow-release agent, and ultrapure water is used as the solvent. The solution is stirred to make it homogeneous. The molar ratio of Ni(NO3)2·6H2O to Fe(NO3)3·9H2O is 1:1.

[0022] Specifically, 6 mmol of Ni(NO3)2·6H2O, Fe(NO3)3·9H2O, a certain amount of 1 mmol of Zn(NO3)2·6H2O, 30 mmol of CH4N2O, and 6 mmol of NH4F were weighed and dispersed in 35 mL of ultrapure water. The mixture was stirred for one hour beforehand to achieve uniform dispersion. The aqueous solution was transferred to a 50 mL Teflon-lined stainless steel autoclave. Clean nickel foam was immersed in the autoclave at room temperature. The autoclave was kept at 120°C for 12 hours. After cooling, the yellow nickel foam containing the precursor was removed, washed several times with water and ethanol, and dried in a vacuum drying oven at 60°C for 6 hours. This product was labeled as NiFeZn-LDHs / NF.

[0023] The zinc-doped nickel-iron hydrotalcite was tested as follows.

[0024] Test 1

[0025] Five vanadium solutions with different initial concentrations were prepared using NaVO3. 25 mL of each solution was placed in a 40 mL glass bottle, and 0.01 g of the prepared zinc-doped nickel-iron layered double hydroxide (LDH) was added to each. The solutions were shaken at 300 rpm for 12 h at room temperature. The vanadium solutions were then filtered through a filter membrane, and the supernatant was collected. The concentration of vanadium in the vanadium solutions after adsorption was measured using ICP-OES (PerkinElmer 8300). Finally, the adsorption capacity of the prepared zinc-doped nickel-iron LDH for vanadium was calculated using the initial and post-adsorption concentrations of vanadium in the solutions. The formula for calculating the adsorption capacity of zinc-doped nickel-iron LDH for vanadium is as follows: ,

[0026] in,

[0027] The adsorption capacity of vanadium is (mg / g).

[0028] V is the volume of solution added (mL);

[0029] m represents the dosage (mg) of the magnesium aluminum hydrotalcite sample.

[0030] and The values ​​represent the initial and post-adsorption vanadium concentrations (mg / L), respectively.

[0031] Test 2

[0032] Six 1g portions of NiFeZn-LDHs / NF were weighed out as adsorbents and added to 100ml of vanadium-containing solution to be adsorbed, with initial concentrations of 200, 500, 1000, 1500, 2000, and 2500 mg / L, pH=7. Adsorption was carried out in a closed conical flask with constant temperature shaking at 20℃ for 24 h.

[0033] The adsorption capacity and adsorption efficiency of NiFeZn-LDHs / NF for vanadium at different initial concentrations are shown in the figures. Figure 1 and Figure 2 The adsorption efficiency of vanadium refers to the ratio of the amount of vanadium adsorbed to the vanadium content in the initial solution.

[0034] As shown in the figure, the highest adsorption capacity of NiFeZn-LDHs / NF for vanadium reached 172.75 mg / g, and the highest adsorption efficiency reached 94%.

[0035] 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 and improvements made within the spirit and principles of the present invention should be included within the scope of the present invention.

Claims

1. A method for adsorbing heavy metal vanadium from mineral processing wastewater, characterized in that: The steps are as follows: S1. Zinc-doped nickel-iron hydrotalcite was synthesized using a hydrothermal method; S2. Zinc-doped nickel-iron hydrotalcite is used to adsorb and remove vanadium from water under neutral conditions. The adsorption time is 0.25-24 hours and the temperature is room temperature. The preparation method of zinc-doped nickel-iron hydrotalcite in step S1 is as follows: weigh a certain amount of Ni(NO3)2·6H2O, Fe(NO3)3·9H2O, Zn(NO3)2·6H2O, CH4N2O, and NH4F, disperse them in ultrapure water, stir for one hour to achieve uniform dispersion, and then transfer them to a stainless steel reactor. The clean nickel foam is immersed at room temperature, and then the temperature of the high-pressure reactor is raised to 120°C and maintained for 12 hours. After cooling, the yellow nickel foam board containing the precursor is taken out, washed several times with water and ethanol, and dried in a vacuum drying oven at 60°C for 6 hours, which is recorded as NiFeZn-LDHs / NF. The molar ratio of Ni(NO3)2·6H2O and Fe(NO3)3·9H2O is 1:1.

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