Optimization of arsenic phytoremediation using Eichhornia crassipes

Abstract

This study aimed to evaluate the pH, phosphate, and nitrate in the process of arsenic absorption by Eichhornia crassipes (water hyacinth), using the surface response methodology, in order to optimize the process. The plants were exposed to a concentration of arsenic of 0.5 mg L (NaAsO) over a period of 10 days. The results indicated optimal levels for the absorption of arsenic by E. crassipes at pH equal to 7.5, absence of phosphate, and minimum nitrate level of 0.0887 mmol L. For the tested concentration, E. crassipes was able to accumulate 498.4 mg kg of As (dry base) in its plant tissue and to reduce 83% of the initial concentration present in the aqueous medium where it was cultivated. The concentration of phosphorus in solution linearly increased the phosphorus content in the plants and negatively influenced the absorption of arsenic. The concentration of 0.5 mg L of As did not significantly affect the relative growth rate (RGR) and the tolerance index (TI). 94% of As (III) initially solubilized in water was converted by the end of the experiment period into As (V). The water hyacinth was important in the phytoremediation of arsenic when cultivated under optimal conditions for its removal.

Arsenic Remediation through Sustainable Phytoremediation Approaches

“…The biomass accumulation and As removal potential of L. gibba were found to be as high as 73.6 t/ha/y and 752 kg As/ha/y, respectively [65]. In another study, E. crassipes was found to accumulate about 498 mg As/kg dry weight from a solution of 0.5 mg/L As in 10 d with a reduction of initial As concentration by 83% [71]. H. verticillata plants were found to remove up to 72% of As from 8 L As (1500 ug/L) medium in 45 d with the maximum As concentration of 388 µg/g dry weight [72].…”

Comparison of Phytoremediation and Filtration for Diamond-mine-tailings Water Treatment

“…CW is a promising technology that involves the use of natural processes that require low maintenance and operational costs [7]. Eichhornia crassipes i.e., the water hyacinth [8], grows widely in tropical regions and often damages local water ecology by covering the entire water surface, thereby preventing sunlight from penetrating into the water [9]. However, this plant shows great promise for application in the phytoremediation of water bodies, as it reduces the amount of pollutants in the water, including the total suspended solids, total dissolved solids, biochemical oxygen demand (BOD), COD, and heavy-metal compounds [10].…”