Abstract

Plant-based coagulants/flocculants are foreseen to be a major progress in water treatment technology owing to their safety, biodegradability and availability, unlike synthetic chemical water refiners such as Al, Fe salts and organic polymers claimed to cause threats to our ecosystem either via their residues in the treated waters or due to their generated toxic sludge. Further, the increasing global awareness about environmental issues is acting as a driving force behind the interest toward the use of green resources as valuable products for water treatment. Substitution of synthetic coagulants/flocculants by such natural materials can not only minimize ecosystem damages and threats, but would also foster the way toward an era of clean technology and a sustainable environment. The present paper reviews works on the most efficient model plant-based coagulants/flocculants, moringa seeds, cactus pads, okra seed pods and mango kernels, via highlighting their effectiveness in treating a variety of waters. This review focuses also on the extracting processes used for their preparation, on the type of their active compounds as well as on water pollutant removal mechanisms. Among the four known coagulation–flocculation phenomenon, both polymer bridging and charge neutralization were assumed to be the main predominant mechanisms of bio-coagulants/bio-flocculants toward water contaminant removal. Further, this paper sheds light on where future works should head aiming to stress on the exploitation of green materials in water remediation. We believe that this review can provide an immediate platform for scientists to intensify their research on more efficient natural products to be used in water processing for the sake of a safer environment.

Graphic abstract

中文翻译：

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迈向绿色技术：一些用于淡水和废水修复的高效模型植物性混凝剂/絮凝剂的综述

摘要

由于基于植物的混凝剂/絮凝剂的安全性，可生物降解性和可利用性，它们被认为是水处理技术的一项重大进步，不像诸如铝，铁盐和有机聚合物之类的合成化学净水剂通过它们对我们的生态系统造成威胁处理过的水中的残留物或由于其产生的有毒污泥。此外，全球对环境问题的意识日益增强，这驱使人们对使用绿色资源作为水处理的有价值产品产生了兴趣。用这种天然材料替代合成混凝剂/絮凝剂不仅可以最大程度地减少生态系统的破坏和威胁，而且还可以为通往清洁技术时代和可持续环境时代铺平道路。本文通过强调最有效的模型植物凝结剂/絮凝剂，辣木种子，仙人掌垫，黄秋葵荚果和芒果仁，对它们的治疗效果进行了综述，着重介绍了它们在处理各种水体中的有效性。这篇综述还着重于用于其制备的提取工艺，其活性化合物的类型以及水污染物去除机理。在四种已知的凝结-絮凝现象中，聚合物桥接和电荷中和被认为是生物凝结剂/生物絮凝剂去除水污染物的主要机制。此外，本文阐明了未来的工作应该去哪里，以强调在水修复中开发绿色材料为重点。

图形摘要