Does fertilizer (N15P15K15) amendment enhance phytoremediation of petroleum-polluted aquatic ecosystem in the presence of water hyacinth (Eichhornia crassipes [Mart.] Solms)?

Use of Biostimulants as a New Approach for the Improvement of Phytoremediation Performance—A Review

Environmental pollution is one of the most pressing global issues, and it requires priority attention. Environmental remediation techniques have been developed over the years and can be applied to polluted sites, but they can have limited effectiveness and high energy consumption and costs. Bioremediation techniques, on the other hand, represent a promising alternative. Among them, phytoremediation is attracting particular attention, a green methodology that relies on the use of plant species to remediate contaminated sites or prevent the dispersion of xenobiotics into the environment. In this review, after a brief introduction focused on pollution and phytoremediation, the use of plant biostimulants (PBs) in the improvement of the remediation effectiveness is proposed. PBs are substances widely used in agriculture to raise crop production and resistance to various types of stress. Recent studies have also documented their ability to counteract the deleterious effects of pollutants on plants, thus increasing the phytoremediation efficiency of some species. The works published to date, reviewed and discussed in the present work, reveal promising prospects in the remediation of polluted environments, especially for heavy metals, when PBs derived from humic substances, protein and amino acid hydrolysate, inorganic salts, microbes, seaweed, plant extracts, and fungi are employed.

Assessment of the Cu(II) and Pb(II) removal efficiency of aqueous solutions by the dry biomass Aguapé: kinetics of adsorption

Plant-based materials are promising adsorbents for treating liquid effluents. This study describes the kinetic and equilibrium parameters that best represent the copper(II) and lead(II) removal process by Eichhornia crassipes (Aguapé) dry biomass from aqueous solution, using a batch adsorption system. The plants were washed, dried, and reduced to small particles. The adsorption kinetics were assessed by varying the metal concentrations in 5, 10, and 20 mg L^-1 and a control treatment (without metals) with a mixture contact time of between 5 and 720 min. Equilibrium data were fitted to the Langmuir and Freundlich models. Kinetic assay revealed fast adsorption: kinetic equilibrium was attained within 2 h with a removal efficiency of ~ 60%. The results demonstrated a fast recovery cycle of metals using the biosorbent. The biomass of E. crassipes is low cost with potential for use as a biosorbent to remove metals from solutions.

Assessment of phytokinetic removal of pollutants of paper mill effluent using water hyacinth (Eichhornia crassipes [Mart.] Solms)

Laboratory experiments were carried out to assess the phytoremediation potential of water hyacinth (Eichhornia crassipes [Mart.] Solms) for the removal of different parameters of the paper mill effluent. The maximum removal efficiency of E. crassipes and phytokinetic removal rate were recorded at 50% concentration of the paper mill effluent followed by 60 days of phytoremediation experiments. The most percent reduction was observed in the contents of electrical conductivity (EC; 62.23%), total dissolved solid (TDS; 72.54%), biochemical oxygen demand (BOD; 79.93%), chemical oxygen demand (COD; 85.66%), total Kjeldhal nitrogen (TKN; 89.27%), P (72.39%), Ca²⁺ (51.79%), Mg²⁺(51.02%), Na⁺ (57.10%) and K⁺(71.47%) and phytokinetic removal rate in the subjects of EC (0.00011 mg l^-1d^-1), TDS (0.045 mg l^-1d^-1), BOD (0.0314 mg l^-1d^-1), COD (0.0461 mg l^-1d^-1), TKN (0.0034 mg l^-1d^-1), P (0.0050 mg l^-1d^-1), Ca²⁺ (0.0045 mg l^-1d^-1), Mg²⁺ (0.003 mg l^-1d^-1), Na⁺ (0.004 mg l^-1d^-1) and K⁺ (0.004 mg l^-1d^-1) after phytoremediation at 60 days. The maximum plant height (120.73 cm), fresh plant biomass (383.54 ± 0.15 gkg^-1) and total chlorophyll content (3.74 ± 0.05 mgg^-1 fwt), crude protein (19.11 mg 100 g^-1 fwt), crude fiber (29.92 mg 100 g^-1 fwt), total carbohydrate (35.22 mg 100 g^-1 fwt) and total ash (26.88 mg 100 g^-1 fwt) of E. crassipes were observed with 50% concentration of the paper mill effluent at 60 days of phytoremediation experiments. The maximum relative growth rate (13.86 gg^-1d^-1) of E. crassipes was detected with 50% concentration of paper mill effluent at 60 days of phytoremediation experiments. Therefore, E. crassipes was recorded to be feasible for the removal of different pollutants of paper mill effluent, responsible for the eutrophication of the aquatic resources.