硝酸铵废液制备新型UAN的作物与土壤生态效应研究

The Effects of A New UAN Recycled from Ammonium Nitrate Wastewater on Crop Growth and Soil Ecological Safety

对印制电路板行业退锡废硝酸、经氨水中和沉淀回收锡产品后产生的高浓度硝酸铵废液进行资源化利用,制备出新型尿素硝酸铵溶液。有必要开展农作物生长试验,以保护人体健康和土壤生态安全。采用大白菜(Brassica bara L.)、玉米(Zea mays L.)幼苗盆栽试验,在水稻土上设置3种施肥处理,分别为不施肥对照(CK)、施用商品尿素硝酸铵溶液(CUAN)、新型尿素硝酸铵溶液(NUAN)。大白菜、玉米幼苗收获后,分别测定植株生物量、有害重金属含量(以鲜质量计),土壤NPK全量和速效含量、土壤有害重金属有效含量、土壤中脲酶和脱氢酶活性。结果表明,施用CUAN和NUAN的大白菜与玉米幼苗干物质每盆质量分别为5.13、5.03 g·pot^(−1),13.82、15.12 g·pot^(−1)。施用CUAN和NUAN处理的大白菜(鲜基)均未检出Hg、Pb,而Cd、As、Cr质量分数分别为0.07、0.08 mg·kg^(−1),0.049、0.018 mg·kg^(−1),0.24、0.08 mg·kg^(−1),主要重金属含量均符合《食品国家安全标准食品中污染物限量》(GB 2762—2012)中叶菜类安全标准;施用CUAN和NUAN处理的玉米幼苗(鲜基)也均未检出Hg、Pb,而Cd、As、Cr质量分数分别为0.06、0.08 mg·kg^(−1),0.035、0.034 mg·kg^(−1),0.82、0.95 mg·kg^(−1),NUAN的施用对玉米幼苗主要重金属指标没有产生负面影响。施用CUAN与NUAN处理的盆栽大白菜土壤脲酶和脱氢酶的活性分别为0.13、0.11 mg·g^(−1)·d^(−1),6.35、6.88 mg·g^(−1)·h^(−1);施用CUAN与NUAN处理的盆栽玉米幼苗土壤脲酶和脱氢酶的活性分别为0.17、0.16 mg·g^(−1)·d^(−1),4.81、4.81 mg·g^(−1)·h^(−1)。所有测定指标的结果表明,两种UAN处理的差异均不显著。因此,NUAN的作物效应、以及对土壤生态的影响与CUAN相当,作为肥料施用是安全的。

A high-concentration ammonium nitrate wastewater was generated from the nitrate wastewater containing tin in the printed circuit board industry,through the recovery of tin products by neutralizing and precipitating with adding ammonia liquor.This ammonium nitrate wastewater was used for resource utilization to produce a new urea ammonium nitrate(NUAN).In this study,the pot experiments of both cabbages(Brassica bara L.)and corn(Zea mays L.)were carried out.There were three treatments,characterizing with no fertilizer control(CK),commercial urea ammonium nitrate solution fertilizer(CUAN),and new urea ammonium nitrate solution fertilizer(NUAN).After harvest,the plant biomass,harmful heavy metals content(fresh weight),total weight and available content of soil NPK,effective content of harmful heavy metals in soil,soil urease activity and dehydrogenase activity were measured.The results showed that the dry weights of cabbage was 5.13 g·pot^(−1) and 5.03 g·pot^(−1) with CUAN and NUAN,while the dry weights of corn seedling was 13.82 g·pot^(−1) and 15.12 g·pot^(−1) with CUAN and NUAN respectively.Mercury(Hg)and lead(Pb)were not detected in cabbage(fresh base)in both CUAN and NUAN groups,but the Cadmium(Cd),arsenic(As)and chromium(Cr)levels were 0.07 mg·kg^(−1),0.049 mg·kg^(−1) and 0.24 mg·kg^(−1) in the CUAN groups,and in the NUAN groups,Cd,As and Cr were 0.08 mg·kg^(−1),0.018 mg·kg^(−1) and 0.08 mg·kg^(−1) respectively.The contents of harmful heavy metals were in line with the National Food Safety Standard Limits of Pollutants in Food(GB 2762-2012).Hg and Pb were not detected in corn seedlings as well,the Cadmium(Cd),arsenic(As)and chromium(Cr)levels in CUAN and NUAN groups were 0.06 mg·kg^(−1) and 0.08 mg·kg^(−1),0.035 mg·kg^(−1) and 0.034 mg·kg^(−1),0.82 mg·kg^(−1) and 0.95 mg·kg^(−1).The effects of NUAN on corn seedling in term of harmful heavy metal contents were not negative.The activity levels of soil urease and dehydrogenase in cabbage were 0.13 mg·g^(−1)·d^(−1) and 0.11 mg·g^(−1)·d^(−1),6.35 mg·g^(−1)·h^(−1) and 6.88 mg·g^(−1)·h^(−1) with CUAN and NUAN separately.While in corn seedling groups,soil urease and dehydrogenase activities were 0.17 mg·g^(−1)·d^(−1) and 0.16 mg·g^(−1)·d^(−1),4.81 mg·g^(−1)·h^(−1) and 4.81 mg·g^(−1)·h^(−1) under CUAN and NUAN situation separatively.The difference between CUAN and NUAN groups was negligible.The biological and soil ecological effects of NUAN are similar to CUAN,so that it was safe to use NUAN as the fertilizer.