|
| Method | Advantages | Disadvantages |
|
| Vapour-phase process | High-purity NPs yielded by the clean process | Limited mass of prepared material, high price of product, agglomeration |
| Milling process | Production of large quantities of crystal powders | Contamination from milling media and atmosphere, difficult to control product morphology |
| Sol-gel method | Very practical, low cost, precise stoichiometry control | High cost of raw materials, health hazard of organic compounds, amorphous final products, need final calcinations at high temperature |
| Hydrothermal and solvothermal process | Efficient and available for many kinds of nanomaterials, synthesis of complex inorganic compounds | Need capping agents and surfactants which affect some properties of the product, large amount of solvent used, high pressure |
| Flame synthesis | Solvent free, product required no subsequent postprocessing, less process waste | Agglomeration of NPs |
| Chemical precipitation | Simplicity, yields final products of near-perfect stoichiometry without high temperature treatment | Use of a lot of chemicals, potentially hazardous waste, postprocessing treatments required to improve purity of the end-product |
| Biological methods: plants | Easy scaled up for large synthesis of NPs, no need of high temperature, energy, pressure, and toxic chemical, reduces cost of microorganism isolation and their culture media | Cannot be manipulated as the choice of NPs through optimized synthesis through genetic engineering, produces low yield of secreted proteins which decrease the synthesis rate |
| Enzymes/microorganism | Cost-effective, biocompatible | Difficult to control size and shape, monodispersed particles, low rate of production, time-consuming culturing of microorganism |
| Bacteria have ability to reduce heavy metal ions and are easy to handle and manipulate |
|
