Nanotechnology has emerged as a significant tool in various fields of science. Synthesis of metal nanoparticles using physical and chemical methods are based on the use of toxic chemicals which have deleterious effect on the environment. To overcome the limitations of chemical methods, green synthesis provides an eco‐friendly and inexpensive alternative path for the synthesis of metal nanoparticles. Since nature provides a variety of products in the form of plants, bacteria, fungi and biopolymers which serve the purpose in a safer way, green resources like plant extracts, certain bacteria, fungus and biopolymers have been used to synthesize metal and metal oxide nanoparticles. Metal nanoparticles as colorimetric sensors gained much attention in recent years due to their sensitive and selective color change which is visible by the naked eye. They are portable and cost effective. This review highlights the green synthesis of metal and metal oxide nanoparticles using plant extracts and biopolymers, and their characterization, mechanism and factors affecting synthesis. Specific application of these green synthesized nanoparticles as colorimetric sensors for the detection of toxic pollutants in water is discussed in detail.

中文翻译：

---

基于绿色合成纳米材料的比色传感器，可检测环境中的有毒物质

纳米技术已经成为科学各个领域中的重要工具。使用物理和化学方法合成金属纳米颗粒的基础是使用对环境具有有害影响的有毒化学物质。为了克服化学方法的局限性，绿色合成为金属纳米粒子的合成提供了一种环保且廉价的替代途径。由于大自然以植物，细菌，真菌和生物聚合物的形式提供了多种产品，它们以更安全的方式发挥作用，因此绿色资源（如植物提取物，某些细菌，真菌和生物聚合物）已用于合成金属和金属氧化物纳米粒子。金属纳米颗粒作为比色传感器，由于其肉眼可见的敏感和选择性颜色变化，近年来备受关注。它们是便携式的且具有成本效益。这篇综述着重介绍了使用植物提取物和生物聚合物进行金属和金属氧化物纳米粒子的绿色合成，以及它们的表征，机理和影响合成的因素。详细讨论了这些绿色合成纳米颗粒作为比色传感器用于检测水中有毒污染物的具体应用。