Alessandrino Luigi, Colombani Nicolò, Aschonitis Vassilis, Eusebi Anna Laura, Mastrocicco Micòl
DiSTABiF - Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Campania University "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy.
SIMAU - Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy.
Sci Total Environ. 2023 Feb 1;858(Pt 1):159806. doi: 10.1016/j.scitotenv.2022.159806. Epub 2022 Oct 28.
Given the large amount of Graphene produced in the last years, there is the need to introduce this new material into a green and circular economy loop. In this study, for the first time, the fate of nutrients and heavy metals in a sandy Calcisol amended with Graphene was monitored and compared to other traditional improvers such as Compost, Zeolites, and Biochar. This was performed via saturated and unsaturated columns' experiments with two different fertilization regimes: one with NPK fertilizer and one with an innovative fertigation water (FW) produced from a pilot wastewater treatment plant. The breakthrough curves of each nutrient and heavy metal were analysed to understand the main processes occurring in saturated and unsaturated conditions, comparing the columns amended with the improvers versus the unamended Controls. Mass balances for each nutrient and heavy metal were developed to infer whether the different soil improvers were effective in minimizing leaching. Graphene, for most cases, behaved as the Control in nutrients' leaching for all the saturated and unsaturated experiments, both with NPK and FW. Biochar increased EC, K, and pH of the leaching water, which could be an issue for the growth of some plants. Compost increased NO leaching in all the experiments. Zeolites showed the best N compounds retention, but great PO leaching in saturated conditions. Heavy metals leachates were analysed only for unsaturated columns (as more representative of field conditions) and found at concentrations well below the limits suggested by the U.S. Environmental Protection Agency. Overall, Graphene performed well in minimizing nutrients and heavy metals leaching, respect to classical improvers. This study is a starting point for field studies that will be critical to have a clear understanding of how Graphene behaves in the environment.
鉴于近年来石墨烯的产量巨大，有必要将这种新材料引入绿色循环经济体系。在本研究中，首次监测了添加石墨烯的砂质石灰土中养分和重金属的去向，并与堆肥、沸石和生物炭等其他传统改良剂进行了比较。这是通过饱和柱和不饱和柱实验进行的，采用了两种不同的施肥方式：一种使用氮磷钾肥料，另一种使用由中试污水处理厂生产的创新灌溉水（FW）。分析了每种养分和重金属的穿透曲线，以了解在饱和和不饱和条件下发生的主要过程，比较添加改良剂的柱体与未改良的对照柱体。建立了每种养分和重金属的质量平衡，以推断不同的土壤改良剂在减少淋溶方面是否有效。在大多数情况下，对于所有饱和和不饱和实验，无论是使用氮磷钾肥料还是FW，石墨烯在养分淋溶方面的表现都与对照相似。生物炭增加了淋溶水的电导率、钾含量和pH值，这可能对某些植物的生长产生影响。在所有实验中，堆肥都增加了硝酸盐的淋溶。沸石对氮化合物的保留效果最佳，但在饱和条件下磷酸盐的淋溶量很大。仅对不饱和柱体（更能代表田间条件）分析了重金属渗滤液，发现其浓度远低于美国环境保护局建议的限值。总体而言，与传统改良剂相比，石墨烯在减少养分和重金属淋溶方面表现良好。这项研究是田间研究的起点，对于清楚了解石墨烯在环境中的行为至关重要。
