International Journal of Phytoremediation最新文献

Methylene blue (MB) contamination in agricultural systems, primarily from industrial wastewater, disrupts plant physiology by interfering with photosynthesis, inhibiting root nutrient uptake, and altering microbial dynamics. This leads to oxidative stress, nutrient imbalances, and stunted growth, reducing crop yields. Hydroxyapatite (HP) has been previously explored for its role in soil remediation and nutrient management, but its potential in alleviating dye-induced oxidative stress in crop plants has not been reported until now. This study is the first to demonstrate that HP can be repurposed as a dual-function biocompatible amendment to both adsorb MB and mitigate its phytotoxic effects in wheat (Triticum aestivum L.) seedlings. Wheat seedlings were hydroponically exposed to MB (20 mg L^-1 and 40 mg L^-1), and key physiological and biochemical parameters were assessed. MB stress significantly reduced chlorophyll a (54%), chlorophyll b (52%), and carotenoids (40%), while increasing hydrogen peroxide (H₂O₂) by 35%-56% and malondialdehyde (MDA) by 109% at MB40 treatment. HP (1 mg L^-1) application improved dry weight (89%) and seedling length (68%), enhanced chlorophyll a (108%), chlorophyll b (84%), and carotenoids (65%), while reducing H₂O₂ (32%) and MDA (48%). Additionally, HP enhanced antioxidant enzyme activities, including ascorbate peroxidase (155%), catalase (88%), and peroxidase (55%) under MB stress. HP alleviated growth inhibition and oxidative stress by causing enhancement of the activity of the enzymes and related metabolites of the xenobiotic detoxification system and the secondary metabolism pathway. These findings suggest that HP effectively alleviates MB-induced oxidative stress, improving photosynthetic pigments and antioxidant defense mechanisms. This research supports HP as a sustainable amendment to enhance crop resilience in contaminated agricultural systems.

In this paper, lignin was chemically extracted from Bombycilaena erecta fibers and modified with branched polyethyleneimine (BPEI) and the resulting samples were applied for the adsorption of two anionic dyes; Acid red 183 (AR183) and Acid blue 25 (AB25) from aqueous suspension. Analytical characterization methods including SEM, FT-IR, TGA/DTG, and XRD were used to analyze the studied samples. The images of the extracted lignin displayed a rough feature. After functionalization of lignin with branched polyethyleneimine, the surface became rougher with the presence of many cavities. FT-IR spectrum of the extracted lignin showed series of absorption peaks characteristics of lignin structure. The XRD diffractograms revealed a wide area under the curve, confirming the amorphous characteristic of the lignin samples. The functionalization with branched polyethyleneimine does not affect the crystallinity of lignin. TGA/DTG exhibited several degradation stages in a wide range of degradation temperature due to the complex molecular structure of lignin. The thermal decomposition of the modified lignin samples occurred at more elevated temperature values compared to unmodified extracted lignin. At adsorption equilibrium (pH = 5, time = 60 min, and T = 19 °C), the highest adsorption capacities reached using the adsorbent lignin-BPEI (5%) were 192 and 135 mg/g for AB25 and AR183, respectively. The adsorption process fitted well to pseudo second order and Freundlich equations. Overall, the prepared aminated lignin was found to be excellent candidate for the decolorization of water rich with anionic dyes.

Carbon-based nanomaterials are becoming increasingly prevalent due to their high degradation rates for various aquatic contaminants. However, their expensive and complex synthesis poses a major challenge. One of the most efficient and easy methods to degrade dyes is by the use of carbon quantum dots (CQDs). This research focuses on the degradation of an aquatic pollutant by deriving CQDs from green sources, as plant part-based CQDs possess the potential to degrade aquatic contaminants. In this study, we first examine the use of Dalbergia sissoo as a method for producing bare or unmodified carbon quantum dots (UCQDs) and S and N co-enriched carbon quantum dots (S, N-CQDs) through a straightforward, rapid, and single-step microwave process. EDX, FTIR, FESEM, XRD, and UV-Visible spectra were utilized to characterize CQDs. The zeta potential of as-synthesized CQDs was also measured. The photocatalytic activity of CQDs was studied by degrading a cationic dye known as Malachite Green (MG) dye, along with optimization of various factors, notably pH, dye concentration, and CQD volume, which were also tuned. S, N-CQDs reported outstanding photocatalytic capacity (95.12%) toward 15 ppm MG dye in bright sunlight at a pH of 9, employing 1 ml of photocatalyst. These CQDs emerged as a promising photocatalyst due to their easy synthesis and remarkable photocatalytic efficiency.

Cadmium (Cd) is a highly toxic heavy metal element widely in the natural environment. To investigate the effect of nano silica (SiO₂ NPs) on the cadmium (Cd) accumulation in Phaseolus vulgaris, SiO₂ NPs (100 and 200 mg/L) was sprayed on the leaves of P. vulgaris, and the growth and Cd accumulation under Cd stress were assessed. SiO₂ NPs increased the biomass, photosynthetic pigment content, peroxidase (POD) activity, and Cd content of P. vulgaris under Cd stress. Compared to Cd treatment, the concentration of 200 mg/L SiO₂ NPs increased the Cd contents in roots and shoots of P. vulgaris by 4.97% and 13.34%, respectively. Furthermore, correlation, principal component, and cluster analyses revealed that the shoot Cd content had the closest relationship with the photosynthetic pigment content and root and shoot biomass. Therefore, SiO₂ NPs can mitigate Cd stress, promote the growth, and increase Cd accumulation of P. vulgaris, which is not suitable for the production of P. vulgaris in Cd contaminated areas.

This study reports the green synthesis of magnetic iron oxide nanoparticles (Fe₃O₄@CP-NPs) using citrus pomace extract as a natural stabilizing and coating agent. Structural and surface characterizations (FE-SEM, XRD, EDX, UV-Vis, FTIR, and VSM) confirmed the successful formation of Fe₃O₄ nanoparticles with functional groups from the extract bound to their surface. Adsorption performance was evaluated using Reactive Yellow 145 (RY145), a representative azo dye pollutant. Batch experiments examined the effects of dye concentration, adsorbent dosage, pH, contact time, and temperature. Under optimal conditions (3.6 g/L dosage, pH 5, 250 mg/L dye), Fe₃O₄@CP-NPs achieved a maximum adsorption capacity of 192.49 mg/g. Equilibrium data were best fitted by the Toth isotherm (R² = 0.999), while adsorption kinetics followed a pseudo-second-order model. Thermodynamic parameters confirmed a spontaneous, exothermic process. Regeneration with NaOH enabled 99.12% dye desorption, with high reusability over several cycles. Notably, a preliminary cost estimation showed that large-scale synthesis could be achieved at ∼0.036 US$/g, underscoring its economic competitiveness compared with conventional adsorbents. This is the first report on the valorization of citrus pomace for producing high-performance magnetic nanoadsorbents for azo (-N = N-) dye removal, highlighting both scientific novelty and environmental relevance.

Nanoparticles (NPs) have found numerous applications in various areas of science, technology, engineering, and mathematics (STEM), including drug delivery, quality control, environmental assessment, and diagnostics. This is primarily because of its environmentally friendly nature and cost-effectiveness. In recent times, NPs have been explored for metal remediation over traditional methods. ZnONPs were produced successfully from Ocimum gratissimum (OG) leaf extract (ZnONP-OG) and characterized using SEM-EDX, XRD, BET, and FTIR. The potency and optimal clean-up conditions for aqueous-bound Cd were investigated using the batch-type adsorption process. The optimal cleanup conditions were observed at a contact time of 15 min, temperature of 303 K, adsorbent dose of 0.5 g, initial concentration of 25 mg/L, and pH of 11. Optimum removal percentage of >93% was observed, and the experimental data best fitted the Langmuir isotherm model (R²:0.999) and the pseudo-second order kinetic model (R²:0.99). Thermodynamic studies revealed a spontaneous and exothermic sorption process for the uptake of Cd from aqueous solutions onto the ZnONP-OG. Overall, the results demonstrated that the ZnONPs synthesized from OG were effective in decontaminating Cd from aqueous solutions and could serve as a potent and cheap substitute compared to conventional adsorbents.

Chromium (Cr) is a highly toxic heavy metal being enters the soil ecosystem by anthropogenic activities, including irrigating wastewater coming from leather industries. Cr adversely affects plant growth and physiology (reduced photosynthesis, oxidative damage, nutritional imbalance). Various methods are being used for its alleviation, but use of organic amendments is gaining importance. That's why current study reports the potential of integrating biochar with Bacillus cereus NM28 to enhance Cr stress tolerance in tomato plants. The results showed that Cr stress significantly decreased tomato growth, but the integrated application of biochar with malic acid and exopolysaccharides producing Bacillus cereus NM28 improved the parameters under study by reducing the adverse effects of Cr stress improving the root dry weight, shoot dry weight, SPAD value, and total chlorophyll contents by 28, 27, 23, 22, and 54%, respectively, at 150 µg mL^-1 of Cr stress. For instance, integrated application has been found to decrease the stress indicators viz. proline and antioxidant status, except ascorbate peroxidase (APX) to alleviate Cr stress. In conclusion, combined use of biochar and Bacillus cereus NM28 offers a promising, eco-friendly strategy to alleviate Cr toxicity in tomato plants, enhancing growth and physiological health while contributing to improved soil quality.

Phytohormone gibberellins (GAs) were utilized to enhance the removal of tetracycline antibiotics and nutrients from swine wastewater by different algal-bacterial symbiosis. Compared to microalgae monoculture, microalgae-activated sludge, and microalgae-Bacillus licheniformis, microalgae-endophytic bacteria showed better growth, photosynthetic, and purification performance. At 50 mg L^-1 GAs addition concentration, the specific growth rate of Chlorella vulgaris-endophytic bacterial (S395-2) system was 0.331 ± 0.03 d^-1, the maximum removal rate of tetracycline (TC), total nitrogen (TN) and total phosphorus (TP) was 96.31 ± 2.73%, 86.37 ± 8.31% and 87.26 ± 8.42%, respectively. The purification effect was much higher than the level of microalgae monoculture without GAs addition (TC removal of 81.33 ± 7.71%, TN and TP removal of 62.51 ± 5.95% and 64.25 ± 6.13%, respectively). In summary, exogenous GAs simultaneously promoted the resistance and biomass accumulation of algal symbiosis, which supplied a theoretical foundation for the treatment of high-concentration nutrients and antibiotics wastewater.

Arsenic in groundwater is a severe problem in México, where its concentration in drinking water exceeds the limit established by the World Health Organization's reference value, and represents a public health problem in the San Luis Potosí, where the affected populations live in semiarid areas without access to arsenic reduction technologies. We developed transgenic Chlamydomonas reinhardtii strains by nuclear and plastid transformation using genes arsC, ɣ-ecs, and acr3 as a cost-effective and noninvasive phytoremediation strategy. The capacity to remove arsenic was evaluated under diverse As(V) concentrations (0.5-2 mg/L) and two phosphate levels (375 and 37.5 µM). The plastid and the double-recombinant strains exhibited substantial As(V) removal capabilities, with a 20% and 80% increase versus wild-type (WT) strain, at the lowest phosphate concentration, the double-recombinant strain exhibited an arsenic uptake rate up to 12 times higher than that of the wild-type (WT) strain, indicating that the genetic modifications enhanced arsenic removal. The double-recombinant microalgae demonstrated exceptional tolerance to As(V), maintaining a µ_max value comparable to that of other strains, indicating sustained cell growth under arsenic stress. This strategy offers a viable platform for arsenic phytoremediation and holds promise for future implementation in public-scale systems.