Study On Remediation Of Cu Pollution In Soil And Water By Remediation Materials

Copper（Cu）,as a special element,is very important to living organisms.Excessive Cu content in soil and water will be toxic to animals and plants.This study took Tongling heavily polluted area as the experimental object,selected hydroxyapatite（HAP）,lime（LM）,biochar（BC）,bio-organic fertilizer（OM）and nanomaterials（SI）to carry out field experiments,compared the late effects of five remediation materials on Cu-contaminated farmland soil.At the same time,indoor adsorption experiments were conducted to test the adsorption effect of SI and sodium alginate composite gel（SACL）on Cu in water,to explore the Cu（Ⅱ） adsorption effect of adsorption materials under different conditions,and the adsorption properties through dynamic model,isothermal adsorption model,thermodynamic model and material characterization analysis.The main results are as follows:1.Field experiment results show that the five restoration materials can continuously reduce the effective Cu content in the soil and the Cu content in the edible parts of the plant.The effective Cu content in the four seasons is reduced by 21.76%～29.04%,22.38%～27.93%,12.09%～31.18%and 14.43%～26.72%,the Cu content in the edible part of the plant has reached the limit of Cu content in food.LM and SI could significantly increase soil p H value.All the remediation materials could increase soil nutrient content in varying degrees.OM and SI improve rapeseed yield,BC and SI improved rice yield.2.Exploring the adsorption performance of SI to Cu（Ⅱ）in water,the results showed that the removal rate of SI for Cu（Ⅱ）was 75.86%,when Cu（Ⅱ）was 200 mg/L,the adsorption time was 180 min and the dosage was 4 g/L.When the p H value of the solution was below 7,the adsorption capacity gradually increased with the increase of the p H value in the initial solution.The adsorption capacity increased with the increase of temperature.The results of adsorption model show that both the Puasi-second-order kinetic model and the Langmuir isothermal adsorption model can better describe the adsorption of Cu（Ⅱ）by SI.At 288 K,298K and 308 K,the maximum theoretical adsorption capacities are 169.15 mg/g,174.82 mg/g and 184.23 mg/g,respectively.The adsorption process of Si on Cu（Ⅱ）is spontaneous,and the high temperature is helpful to the adsorption process.The results show that after adsorption,the rod-like micropores on the surface are filled,and the gap structure is greatly reduced.The adsorption Si contains Cu element.Compared with before and after adsorption,the peak values of some main functional groups in SI have changed.3.SACL was prepared from SI,SA and PEO by chemical crosslinking.The adsorption performance of SACL on Cu（Ⅱ）was studied.The results showed that when the concentration of Cu（Ⅱ）was 200 mg/L,the adsorption time was 180 min,and the addition amount was 80g/L,the removal rate of Cu（Ⅱ）by SACL was 96.72%.The p H value of the solution had a great influence on the adsorption process,and the adsorption capacity was the largest when the p H value of the solution was 4.The increase of temperature leads to the increase of adsorption capacity.The results of the adsorption model show that both the Puasi-second-order kinetic model and the Langmuir model can describe the adsorption of Cu（Ⅱ）by SACL.At 288 K,298 K and 308 K,the maximum theoretical adsorption capacity is 4.38 mg/g,5.61 mg/g and 6.78 mg/g, respectively.The process of SACL adsorption of Cu（Ⅱ）is spontaneous,and the higher the temperature,the more favorable the SACL adsorption of Cu（Ⅱ）.The characterization results show that most of the pores inside the SACL are filled with the Cu（Ⅱ）,with a lot of Cu²⁺in the solution adsorbed on the internal pore walls.The adsorbed SACL contains more Cu elements;some of the main functional group peaks within the SACL have changed before and after adsorption.The regeneration performance results indicate that the SACL removal rate of Cu（Ⅱ）after four adsorption-detachment exceeds 85%.