International Journal of Phytoremediation最新文献

The synthesis of catalysts has gained specific concern due to their versatile applications in particular azo dye decolorization. In the current work, metallic nanoparticles (copper and silver) were In-situ biosynthesised using Allium sativum and Chondrilla juncea extract. The obtained Allium-copper oxide and Allium-silver oxide materials were analyzed using SEM, TEM, FT-IR, TGA-DTG, SEM, TEM, and XRD techniques. Allium peels had a rough surface, with nanoparticles equally distributed over it. The crystal structure of Allium peels was altered after the addition of CuO and AgO nanoparticles. The highest residual mass values in the prepared materials indicated that the metallic nanoparticles were, in situ, formed. The prepared materials had worse thermal stability than Allium peel powders. The azo dyes, Calmagite and Naphthol Blue Black B were tested in the catalytic power of the resulting materials. The decolorization process was affected by the dye structure, amount of H₂O₂, dye concentration, time of reaction, and temperature of the bath. The activation energy values for Allium-CuO were 18.44 kJ mol^-1 for calmagite, and 23.28 kJ mol^-1 for naphthol blue black, respectively. Nevertheless, the energy values for Allium-AgO were 50.01 kJ mol^-1 for calmagite and 12.44 kJ mol^-1 for Naphthol blue black. The calculated low energy values for the prepared materials suggested the high efficiency of the use of these catalysts in azo dye decolorization under the change of some main experimental conditions.

Commercial microalgae production is often interrupted by contamination, leading to short production cycles, reinoculation needs, and culture collapses, significantly increasing costs. This study focuses on investigating Recirculated Sedimentation Application (RSA) to control contamination in microalgae culture systems used for wastewater treatment. Chlorella vulgaris culture was grown in an unsterilized mixture of tertiary treatment effluent and centrate of anaerobic digestion wastewater sludge over a 90-day experimental period. 60 L raceway reactor was operated under a light intensity of 275 μM m^-2.s^-1 with a 16:8 h light-dark photoperiod. To evaluate the effect of RSA on biological-based problems, the experiment was conducted in three phases. The benefits of utilizing RSA were established through the following observations: effective removal of contaminants at an acceptable level without releasing the culture; extension of the biofilm formation time on the inner walls; inhibition of heterotrophic bacteria and nitrification; enhancement of the suspended solids retention capacity of the raceway tank (up to 770 mg.L^-1); and improvement in ammonium removal rate to approximately 30 mg.L^-1d^-1. The ideal salinity level for both ammonium removal and biomass concentration in RSA should be below 0.02%. These findings demonstrate the potential of phycoremediation for sustainable wastewater treatment and contribute to environmental bioremediation strategies.

This study was developed to evaluate the removal potential of ibuprofen, naproxen and 17-β-estradiol in artificial wetlands constructed on a laboratory scale, using eight experimental devices planted with L. octovalvis species, tested with gravel substrate and without gravel substrate, which were fortified with synthetic mixtures at concentrations of 1, 2 and 5 mg/L of the three compounds, during a batch exposure time of nine days. The removal efficiency for 17-β-estradiol was 94.5 ± 2.47%, followed by ibuprofen 94.03 ± 1.96% and naproxen 81.57 ± 8.74%, respectively. The treatment with the highest removal was the one performed without the presence of gravel substrate. The highest removal efficiency occurred from the third day of exposure for the three compounds, so it was established as the optimum residence time. The model that best explained the adsorption process of the three compounds studied, was the Langmuir isotherm. The observed results demonstrate that L. octovalvis can be used as a native species in artificial wetlands for the efficient removal of pharmaceutical compounds.

First time in this study, hybrid Cu nanoflowers (Cu hNFs) were synthesized with Cystosphaera jacquinotii algae extract and the pH-dependent catalytic activities of hNFs synthesized under optimum conditions against brilliant blue and methylene blue dyes were determined. Ideal morphology of hNFs, were synthesized by using 1 ml extract in PBS (pH 7.4). The diameter and petal thickness of optimum synthesized hNF were 7-22 µm, and 35.5 nm, respectively. Main skeleton component (C, O, P, and Cu) of hNFs were determined by EDX. The presence of functional groups and primary phosphate crystals formed by Cu and phosphate reaction in the PBS buffer were confirmed by FT-IR analysis. The hNFs exhibited the antioxidant activity (IC₅₀ = 1.27 mg/ml, R² = 0.6971) against to DPPH (2,2-diphenyl-1- (2,4,6-trinitrophenyl) hydrazyl). hNFs degraded methylene blue and brilliant blue dyes at the highest at pH 9 (73.85%) and pH 5 (68.19%) media, respectively. Catalytic activities of hNFs against methylene blue and brilliant blue dyes were explained by Fenton mechanism. The findings are thought to be used in new type hNF synthesis and various environmental applications.

The efficacy of phytoextraction for remediating heavy-metal contaminated soil depends on the bioavailability of the heavy metals and plant growth. In this study, we employed a synergistic system comprising water-soluble chitosan and the novel Cd mobilization bacteria, Serratia sp. K6 (hereafter K6), to enhance cadmium (Cd) extraction by Lolium perenne L. (ryegrass). The application of chitosan and K6 resulted in an increase in the biomass of ryegrass by 11.81% and Cd accumulation by 73.99% and effective-state Cd by 43.69% and pH decreased by 4.67%, compared to the control group. Microbiome and metabolomics analyses revealed significant alterations in the inter-root microbial ommunity, with rhizobacteria such as Sphingomonas, Nocardioides, and Bacillus likely contributing to enhanced plant growth and Cd accumulation in response to chitosan and K6 addition. Additionally, the contents of various organic acids, amino acids, lipids, and other metabolites exhibited significant changes under different additive treatments, suggesting that ryegrass can regulate its own metabolites to resist Cd stress. This study provides valuable insights into the effects of additives on phytoextraction efficiency and the soil bacterial community, offering a promising approach for phytoremediation of Cd-contaminated soils.

Coal mine drainage (CMD) is an environmental threat due to its high volume, low pH, presence of toxic metals, and absence of biodegradable organics. The present study aims to treat CMD in a horizontal sub-surface flow constructed wetland (CW) using dairy wastewater as an organic source. CW was planted with Typha angustifolia. Characteristics of synthetic CMD were (except pH, all unit mg/L) pH 1.9; Fe: 100, ${\text{SO}}_4^{2-}$: 1,000, Mn: 6, Zn: 5, Co: 1, Ni: 1, and Cr: 1. CMD was mixed with synthetic dairy wastewater (pH: 5.05, COD: 2,700 mg/L, BOD: 1,600 mg/L) in the ratio of 3:1. Alkalinity of 120-190 mg/L CaCO₃ was generated and effluent pH improved from 2.2 to 6.6. Metals precipitated as metal sulfide or hydroxide. Sulfate removal was hindered due to the synergistic toxicity of several metals. Except for Mn, all other effluent parameters were within the discharge limit for disposal in inland surface water.

This review addresses plant interactions with HMs, emphasizing defence mechanisms and the role of chelating agents, antioxidants and various elicitor molecules in mitigating metal toxicity in plants. To combat soil contamination with HMs, chelate assisted phytoextraction using application of natural or synthetic aminopolycarboxylic acids is an effective strategy. Plants also employ diverse signaling pathways, including hormones, calcium, reactive oxygen species, nitric oxide, and Mitogen-Activated Protein Kinases influencing gene expression and defence mechanisms to counter HM stress. Phytohormones enhance the enzymatic and non-enzymatic antioxidant defence mechanism and the level of secondary metabolites in plants when exposed to HM stress. Also it activates genes responsible for DNA repair mechanism. In addition, the plant hormones can also regulate the activity of several transporters of HMs, thereby preventing their entry into the cell. Elicitor molecules regulate metal and metalloid absorption, sequestration and transport in plants. Combining of different elicitors like jasmonic acid, calcium, salicylic acid etc. effectively mitigates metal and metalloid stress in plants. Moreover, microbes including bacteria and fungi, offer eco-friendly and efficient solution for HM remediation. Understanding these elicitors, microbes and various signaling pathways is crucial for developing strategies to enhance plant resilience to metal and metalloid stress.

Heavy metals and petroleum oil are the two most important contaminants in the environment. Currently, phytoremediation is regarded as an effective and affordable solution that allows the attenuation of toxic pollutants through the use of plants. Not many studies are carried out regarding the use of aromatic plants capable of remediating soil that is co-contaminated by heavy metal and petroleum hydrocarbons. A pot experiment was conducted to investigate the influence of cadmium-resistant PGPR Micrococcus luteus on the phytoremediation efficiency of Ocimum gratissimum in Cd and petroleum co-contaminated soil. The plants were harvested after 60 days of treatment and their growth and biomass were determined. The accumulation of Cd in plant shoots and roots was determined. The residual petroleum hydrocarbon concentration during the 60 days of the phytoremediation experiment was determined using GC-FID. O. gratissimum with M. luteus showed the highest Cd accumulation (14.05 mg kg^-1) and the highest reduction of TPH (46.64%). M. luteus ameliorated contaminant toxicity and promoted biomass production of O. gratissimum. These results demonstrated that O. gratissimum in combination with M. luteus can be efficiently used to remediate Cd and petroleum-co-contaminated soils.

Phytoremediation of manganese (Mn)-contaminated water requires the selection of Mn-tolerant species. This study reports on physiological changes and Mn bioaccumulation in the aquatic macrophyte Pistia stratiotes cultivated under various MnCl₂ concentrations: control, 80, 340, 600, 1000, 2000, and 4000 µM. Few visual symptoms of Mn toxicity, such as chlorosis, were observed after 10 days, especially in plants treated with 2000 and 4000 µM MnCl₂. High Mn accumulation was recorded, with maximum values of 23,700 and 24,600 µg g^-1 DW in the shoots and roots, respectively, at 4000 µM Mn, contrasting with 825.01 and 1587.53 µg g^-1 DW in control plants. Cellular fractioning showed that Mn in shoots and roots was mainly associated with the cell wall, with approximately 90% of the Mn in roots detected in the apoplast. There were no significant changes in net CO₂ assimilation or respiratory rates after 5 and 10 days of Mn exposure. These results demonstrate that P. stratiotes is a Mn hyperaccumulator species with excellent phytoremediation potential, as shown by its high bioaccumulation capacity and its ability to maintain photosynthetic efficiency under Mn stress.