Eichhornia crassipes (Mart.) Solms (natural or carbonized) as biosorbent to remove pollutants in water

The prolific aquatic herb Eichhornia crassipes considered a pest in many countries can cause damage such as obstruction of water flows and impair the locomotion of fishing boats. However, E. crassipes is renewable, inexpensive, and widely available in nature, and its ability to adsorb recalcitrant pollutants with mutagenic and carcinogenic properties, including synthetic dyes and heavy metals, has been extensively studied by the scientific community. This review paper analyzes previous reports concerning the use of E. crassipes (in the natural and carbonized form) as an adsorbent for heavy metal cations and textile dye. The adsorptive capacity of E. crassipes, the best conditions (adsorbent dosage, pH, and temperature) for the removal of these pollutants, the mechanism of adsorption, and the comparison between natural and carbonized forms (advantages and disadvantages) are discussed. All the results revised in this review indicated that the use of E. crassipes (and its carbon derived) as adsorbent is promising and is an excellent material to be applied in the water treatment. It could be used in the actual technologies for the treatment of contaminated water by heavy metals and textile dyes; however, more studies need to be made on scale-up, economy projects, and related issues, to be finally implemented in wastewater treatment plants.