Green walls can provide an aesthetic approach to treat domestic greywater in urban landscapes. However, the widespread adoption of green walls for greywater treatment depends on its performance to remove the emerging contaminants from greywater such as xenobiotic organic compounds (XOCs). In this study, the performance of five lightweight green wall media types (zeolite, perlite, date seeds, coffee grinds, and coco coir) was evaluated for the removal of six XOCs representing a range of hydrophilic to hydrophobic organic micropollutants in domestic greywater (acetaminophen, diethyltoluamide, bisphenol A, oxybenzone, triclosan, nonylphenol). The adsorption affinity of targeted XOCs on different green wall media types, the role of contact time on XOCs removal, and the impact of background pollutants in greywater matrix on the adsorption of XOCs were analysed. Results indicate that removal of XOCs was higher using carbonaceous waste materials (date seeds, coffee grinds, and coco coir) as compared to natural minerals (zeolite and perlite). Moreover, the adsorption of XOCs increased with the increase in pollutant hydrophobicity. All XOCs showed highest removal using coco coir with fast adsorption kinetics, achieving 90% of the removal in 30 min. The only exception was acetaminophen that showed best removal using zeolite but exhibited slow adsorption kinetics with 90% of the removal attained in 24 h. The initial adsorption kinetics (<30 min) of XOCs in greywater were adversely affected by the presence of background pollutants, indicating the need of higher residence time of greywater in green wall system for better removal of XOCs. Based on the findings of this batch study, it is recommended to design a green wall system with more than 30 min of greywater residence time using a mixture of coco coir and zeolite for effective removal of XOCs from domestic greywater.

绿色墙壁可以提供一种美学方法来处理城市景观中的家庭灰水。然而，绿墙用于灰水处理的广泛采用取决于其从灰水中去除新兴污染物（如外源性有机化合物 (XOCs)）的性能。在这项研究中，评估了五种轻质绿色壁介质类型（沸石、珍珠岩、枣籽、咖啡研磨物和椰壳）的性能，以去除六种 XOC，这些 XOC 代表了家庭灰水中一系列亲水性到疏水性有机微污染物（对乙酰氨基酚） 、二乙基甲苯甲酰胺、双酚A、氧苯酮、三氯生、壬基酚）。目标 XOCs 在不同绿壁介质类型上的吸附亲和力，接触时间对 XOCs 去除的作用，分析了灰水基质中背景污染物对XOCs吸附的影响。结果表明，与天然矿物（沸石和珍珠岩）相比，使用含碳废料（枣子、咖啡研磨物和椰壳）去除 XOCs 的效果更高。此外，XOCs 的吸附随着污染物疏水性的增加而增加。所有 XOC 使用具有快速吸附动力学的椰壳纤维显示出最高的去除率，在 30 分钟内达到 90% 的去除率。唯一的例外是对乙酰氨基酚，它显示出使用沸石的最佳去除效果，但表现出缓慢的吸附动力学，90% 的去除在 24 小时内达到。XOCs 在灰水中的初始吸附动力学（<30 分钟）受到背景污染物存在的不利影响，表明需要更长的灰水在绿墙系统中的停留时间才能更好地去除 XOC。根据本批次研究的结果，建议使用椰子壳和沸石的混合物设计灰水停留时间超过 30 分钟的绿墙系统，以有效去除生活灰水中的 XOCs。