Development Of Fe₃O₄ Magnetic Nanomaterials And Their Removal Of Pollutants In Water

Magnetic nanomaterials were increasingly used in water treatment,and Fe₃O₄ magnetic nanomaterials have also become a research hotspot.The Fe₃O₄magnetic nanomaterials used in this article was prepared by the co-precipitation method.By modifying the magnetic nanomaterials,the removal effect of pollutants(P,SO₄^2-,Fe²⁺,Cu²⁺)in water can be increased.The preparation of environmentally-friendly and economical magnetic nanomaterials provides a certain reference basis for future water treatment research.The research content of this paper mainly includes:(1)The Fe₃O₄ magnetic nanomaterial was prepared by the co-precipitation method,and the lanthanum-based magnetic nanomaterial was prepared by modifying the magnetic nanomaterial by optimizing lanthanum chloride.Material characterization was carried out by SEM,X-ray,specific surface area analysis,magnetic separation effect,etc.The results showed that the material was nanometer-sized,a specific surface area was 80.47 cm²·g^-1,average was 13.09 nm,and lanthanum chloride successfully adhered to the surface of Fe₃O₄ particles.The material can be solid-liquid separate after 20 s.(2)Study the effect of the prepared lanthanum-based magnetic nanomaterials to remove P,and the process analyzed through the selection of the adsorbent,the determination of the dosage of the adsorbent,the influence of p H on the adsorption process,the adsorption kinetics and the adsorption isotherm.The results showed that the La/Fe ratio was 3:1,the adsorbent dosage was 0.2 g,and the p H was 6,the lanthanum-based magnetic nanomaterials have the best P removal effect,and the adsorption capacity can reach 47.36mg/g.Through the study of adsorption kinetics,it was found that the removal of P by lanthanum-based magnetic nanomaterials can be achieved in as little as 30 minutes.Through the study of adsorption isotherms,it was found that the removal of P by this adsorbent fits the Langmuir equation,the correlation coefficient R² is 0.9954,and the adsorption process was a single-layer adsorption.On the basis of the above experiments,experiments have been carried out on the repeatability of the adsorbent.The results showed that the lanthanum-based magnetic nanomaterials still have a high adsorption effect after being reused for 5 times,and the adsorption efficiency was reduced from the original 95.4%to 92.53%.(3)The prepared Fe₃O₄ magnetic nanomaterials were modified with fly ash,and the adsorption effect of the adsorbent on SO₄^2-,Fe²⁺,and Cu²⁺was studied.First,characterize and analyze the prepared fly ash magnetic nanomaterials,including SEM characterization and energy spectrum analysis,X-ray,specific surface area and nitrogen adsorption-desorption analysis,magnetic separation effect,etc.The average pore diameter of the material was8.11 nm,and solid-liquid separation can be achieved within 25 s.(4)In order to study the adsorption of SO₄^2-,Fe²⁺,Cu²⁺by fly ash magnetic nanomaterials,the most suitable fly ash/Fe adsorbent was selected through adsorption experiments,and the optimal adsorbent was used for the adsorbent dosage,p H,adsorption kinetics,adsorption isotherms.Through research,it was found that the adsorption of SO₄^2-by the fly ash magnetic nanomaterials was 15:1 when the mass ratio of fly ash/Fe was 15:1,the adsorbent dosage was 0.2 g,and the p H was 5,the adsorption effect was the best,and the adsorption amount was 23.82 mg/g.Through research on adsorption kinetics,it was found that SO₄^2-can reach adsorption equilibrium within 120 minutes.At the same time,SO₄^2-was more suitable for quasi-first-order kinetic models with a correlation coefficient of 0.9645,and the q_e under first-order kinetics was 23.93 mg/g.The Langmuir equation can explanation adsorption isotherm conforms.The adsorption isotherm equation fits better with Langmuir,with a correlation coefficient of R² of 0.9883 and a maximum adsorption of 48.17 mg/g;FMH/Fe mass ratio of 15:1 has the best adsorption effect for Fe²⁺,When the adsorption amount was 0.15 g,the most effective adsorption was obtained under neutral or alkaline p H conditions.The adsorption kinetics of the adsorbent found that the adsorption of Fe²⁺for 60minutes can be achieved.The adsorption capacity was 41.85 mg/g.The adsorption process of Fe²⁺was more in line with the quasi-secondary dynamics.The q_e was 41.64 mg/g and the correlation coefficient was 0.9987.Langmuir equation was closer to its isotherm,R² was 0.9822,the adsorption capacity was115.34 mg/g;The adsorption capacity of Cu²⁺was 53.28 mg/g when the adsorption dose was 0.05 g and the p H was 9.Through the study of adsorption kinetics,it was found that Cu²⁺can achieve adsorption saturation within 120minutes,it can be explained by quasi-second-order kinetics.The correlation coefficient was 0.9739,and the q_e was 53.33 mg/g under this model.The adsorption isotherm results showed that the adsorption of Cu²⁺fitted the Langmuir equation,R² was 0.9895,and the Max adsorption was 146.66 mg/g.These three kinds of ions by fly ash magnetic nanomaterials was chemical adsorption,and it was single-layer adsorption.Finally,the regeneration of the adsorbent was studied.The adsorption efficiency of SO₄^2-,Fe²⁺,Cu²⁺was reduced from 53.1%,67.3%,and 89.73%to 45.37%,60.51%,and 83.02%,respectively,with high stability.(5)In order to explore the practical application of the adsorbent,lanthanum-based magnetic nanomaterials were used to adsorb fresh water in actual water bodies.The concentration of SO₄^2-,NO₃^-and Cl^-before and after adsorption did not change much,and the concentration of Ca²⁺decreased by8.84 mg/L,the concentration of Mg²⁺decreased by 10.21 mg/L,and the concentration of P changed from 2.54 mg/L before treatment to 0.59 mg/L;Using fly ash magnetic nano-materials,the actual water body acid mineral water was tested.The results show that the fly ash magnetic nano material has a certain removal effect on acid mineral water.The removal rates of Fe²⁺,Fe³⁺,Zn,Mn and Mg²⁺in acid mineral water were 83.43%,82.96%,81.76%,76.88%and 14.18%.For anions in acid mineral water,the removal rates of SO₄^2-,NO₃^-and NH₄⁺were 48.79%,25.93% and 22.37%,respectively.