| Heavy metal pollution is a serious threat to human health.The strong adsorption of sodium alginate composite gel,the multifunctional group structure of humic acid,and the passivation of heavy metals under Pb(Ⅱ)pollution have attracted the attention of scholars and become one of the current research hotspots.In this thesis,the removal of Pb(Ⅱ)and Zn(Ⅱ)from wastewater by sodium alginate composite gel was explored through two experiments such as indoor adsorption and outdoor potting,and the removal rate and adsorption in solution were obtained from the adsorption time,initial ion mass concentration,temperature,adsorbent dose and pH of sodium alginate composite gel on Pb(Ⅱ)and Zn(Ⅱ)in wastewater.The effects of applying sodium alginate complex gel and humic acid material on soil physicochemical properties,soil heavy metal Pb-Zn content and growth of Brassica juncea were investigated by outdoor pot experiments.The adsorption test results showed that the removal of Pb(Ⅱ)and Zn(Ⅱ)from the wastewater by the sodium alginate composite gel was 95.31% and 93.96%,respectively.The adsorption kinetic process of sodium alginate composite gel was best fitted by the pseudosecondary kinetic equation,and the isothermal adsorption model for Pb(Ⅱ)was in accordance with the Fruendlich model and for Zn(Ⅱ)was in accordance with the Langmuir model.Combined with SEM,EDS and FTIR pattern analysis,the adsorption process was dominated by chemisorption.The outdoor pot experiments showed that the application of sodium alginate complex gel and humic acid could improve the physicochemical properties of soil,soil nutrient content and physicochemical properties of cabbage growth,and the A2+B2 treatment and A2+B3 treatment significantly increased the organic matter content of soil by 26.02% and 36.99% and the effective phosphorus content by 4.26% and 7.90%,respectively;the starch content in cabbage in B2 treatment and B3 treatment The B2 and B3 treatments increased the starch content of cabbage from 4.37% to 4.67% and significantly increased the height of cabbage plants by 17.80% and 11.27%,respectively;the B3 treatment increased the alkaline nitrogen content of soil by 10.18% and the effective potassium content of soil by 9.20%.The application of sodium alginate complex gel and humic acid material had less effect on the total amount of soil Pb and Zn and was able to reduce the effective state content of Pb and Zn in the soil and in the plant of chard.Relative to the CK treatment,the A2 treatment,A2+B3 treatment,B1 treatment,B2 treatment and B3 treatment significantly reduced the effective Zn content in the soil by 3.92%,5.14%,4.35%,4.84%and The A2+B3,B2 and B3 treatments significantly reduced the above-ground total lead content of the plants by 4.62%,3.84% and 7.92%,and the below-ground total lead content of the plants by 4.02%,5.86% and 8.41%,respectively;the A2+B3 and B3 treatments significantly reduced the above-ground total Zn content of the plants by 6.69%,respectively.The A2+B3 and B3 treatments significantly reduced the above-ground total Zn content of the plants by 6.69% and 6.12%,and the below-ground total Zn content of the plants by 2.78%and 2.22%,respectively.In conclusion,the sodium alginate composite gel was effective in adsorbing Pb(Ⅱ)and Zn(Ⅱ)in wastewater,and the treatments of medium amount of sodium alginate composite gel and high amount of humic acid,medium amount of humic acid and high amount of humic acid reduced the effective content of Pb and Zn in soil and the total amount of Pb and Zn in leaves and roots of Brassica juncea to a greater extent,and improved the physicochemical properties and soil nutrients of potted soil,thus promoting The treatment with humic acid and high levels of humic acid reduced to a greater extent the effectiveness of Pb-Zn in the soil and the total Pb-Zn in the leaves and roots of cabbage. |
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