N-nitrosodiphenylamine (NDPhA) is soluble in water and highly toxic. Exposure to NDPhA even at low concentrations for a long period can cause several health effects. Hence the removal of NDPhA from aqueous samples using a widely abundant and economical adsorbent is highly challenging. In this study, a highly efficient, eco-friendly, and low-cost adsorbent was derived from the dead leaves of Halodule uninervis seagrass (SG) without any chemical modifications. The derived adsorbent was characterized and investigated for the removal of NDPhA from aqueous solutions. The effects of solution pH, contact time, adsorbent dosage, and adsorbate concentration were studied and optimized. The SG adsorbent showed a significant removal efficiency of 83% for NDPhA from wastewater solution using 1 g L⁻¹ adsorbent. The maximum adsorption capacity for SG was found to be 64.84 mg g⁻¹ at neutral pH and room temperature. The adsorption isotherm results fitted with the Langmuir model and followed pseudo-second-order kinetics. From the thermodynamic parameters, it has been found that the adsorption of NDPhA onto SG adsorbent is favorable, endothermic, and the chemical adsorption mechanism is predominant. This study indicated that SG adsorbent is reusable and can be easily regenerated and reused at least three times with a slight decrease in its removal efficiency.

中文翻译：

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源自“Halodule uninervis”的经济且环保的吸附剂，可有效去除废水中的 N-亚硝基二苯胺：平衡、可重复使用性和机理研究

N-亚硝基二苯胺（NDPhA）易溶于水，有剧毒。即使长期接触低浓度的 NDPhA，也会对健康造成多种影响。因此，使用广泛且经济的吸附剂从水样中去除 NDPhA 极具挑战性。本研究从Halodule uninervis海草（SG）的枯叶中提取出一种高效、环保、低成本的吸附剂，不含任何化学物质。化学修饰。对衍生的吸附剂进行了表征并研究了其从水溶液中去除 NDPhA 的效果。研究并优化了溶液pH、接触时间、吸附剂用量和吸附物浓度的影响。使用 1 g L^-1 吸附剂，SG 吸附剂对废水中的 NDPhA 的去除效率高达 83%。在中性 pH 值和室温下，SG 的最大吸附容量为 64.84mg g^-1。吸附等温线结果符合Langmuir模型并遵循准二级动力学。从热力学参数来看，SG吸附剂对NDPhA的吸附是有利的、吸热的，且化学吸附机制占主导地位。研究表明，SG吸附剂可重复使用，且易于再生，重复使用至少3次，去除效率略有下降。