Cultivars and oil extraction techniques affect Cd/Pb contents and health risks in oil of rapeseed grown on Cd/Pb-contaminated farmland

Substitute planting with rapeseed offers promise for safely using large areas of Cd/Pb-contaminated farmland.Cd/Pb distributions during rapeseed oil production were investigated and health risks posed by the oil were assessed.Tests were performed using three cultivars(Brassica rapa SYH and ZS100 and Brassica napus QY-1)and four oil extraction techniques(mechanical and low-temperature pressing and n-hexane and subcritical low-temperature butane extraction).The amounts of Cd and Pb in oil were 0.73%-8.44%and 3.14%-11.76%,respectively,of the amounts in rapeseed and were strongly affected by the cultivar and oil extraction technique.The heavy metal(HM)concentrations were lower in solvent-extracted oil(particularly subcritical low-temperature butane extracted oil,in which HMs were not detected)than mechanically pressed oil.The Cd and Pb transfer indices were lower(meaning larger proportions of HMs were retained by the rapeseed meal)for B.rapa than B.napus.This was attributed to a high HM binding protein content of B.rapa seed.Health risks to humans were assessed using a probabilistic risk assessment model.The carcinogenic risk was mainly(97.1%-99.9%)caused by Cd and poses more concern than non-carcinogenic risk.Stronger health risks are posed by mechanically pressed than solvent-extracted oil,and higher carcinogenic risks are posed to people living in rural areas than urban areas.Substitute planting with B.rapa and extracting oil with organic solvent(preferably subcritical low-temperature butane)are optimal for safely utilizing Cd/Pb-contaminated soil.Attention should be paid to the health risks posed by Cd in oil to rural populations.

New Approach to Lightning Strike Risk Assessment of Wind Farm

In the past,lightning strike risk assessment of buildings mainly referred to the Protection against Lightning—Part 2:Risk Management(IEC 62305-2-2010)based on protection angle method.Lightning strike risk assessment of wind farms was conducted according to the Lightning Protection for Wind Energy System(IEC 61400-24-2019),which proposed the method of lightning strike risk assessment for wind turbine.In fact,the basic idea of the two is the same,that is,the source of the lightning strike wind turbine is transformed from the former S1-S4 to the latter N D-N DJ.According to the above method,wind farm was evaluated,and it has been proved that the practice can not achieve good results.After 2018,China has issued the Guide to Evaluation of Lightning Protection Technology in Buildings(T/GZLY 3-2022)and the Technical Specifications for Lightning Interception in Forest Areas(T/LYCY 4062-2024)based on semicircle protection,in which the source of risk defined by lightning point was closer to the reality,highly targeted and effective.Taking offshore wind farm as an example,this paper introduced a new method of establishing six evaluation indicators to determine the risk level according to the principle of compliance and the new protection technology of semi-circular method,which can be used as a reference for technical personnel.

磁性助凝剂资源化制备及强化污染物沉淀分离

通过高温碳化处理,研发并优化磁性助凝剂的资源化制备,并回用于混凝过程强化污染物的沉淀分离。采用磁化曲线、扫描电镜等表征手段,对不同高温制备得到的磁性助剂进行结构及形貌的表征。进一步对混凝过程中絮体的粒度粒型分析得知,磁性助剂有利于污染物的沉淀分离,加入700℃碳化后的磁性助剂(PFS:RW700=1:1.43)使污染物的沉淀分离效率提高至99.45%。磁性助剂带有的磁性使助剂易被絮体包裹,从而加速沉降;磁性助剂中含大量的碳且表面带有羧基等官能团,具有一定的吸附能力;经高温碳化结晶度增加且颗粒大小均一,有利于成核加快絮体增长。通过优化磁性助剂与聚合硫酸铁(PFS)的投加比,仍保持较高的污染物去除率,与活性炭相比,水处理成本降低了2 RMB/t,为解决混凝污泥资源化途径提供技术支撑。

混凝污泥的资源化回收及其电化学性能

将混凝污泥碳化后制成电极材料,通过红外光谱和X射线衍射对污泥的官能团结构与晶型进行表征,采用循环伏安和线性扫描伏安法研究不同碳化温度下所制电极材料的电化学性能,并应用于电芬顿体系催化降解双酚A。结果表明,混凝污泥的主要成分为含碳和铁元素的复合物,高温碳化后污泥的结晶度增强。所制电极在电芬顿体系中显示出良好的电催化活性。外部投加Fe2+条件下,经900℃碳化的电极材料为阴极对双酚A的去除率最高,电解130 min后去除率高达99.2%。表明在电化学芬顿法废水处理中有一定的应用前景。