Phytoremediaton of diethylene glycol contaminated wastewater by Echinodorus cordifolius

Diethylene glycol (DEG) is one of several diols used as a raw material in the production of plasticizers and polyester resins. It has been associated with a number of mass poisonings in several countries. Conventional methods of remediation of DEG contaminated wastewaters are still not very effective. This paper presents an alternative method for remediation of DEG-contaminated waters using the plant Echinodorus cordifolius. The effects of DEG on E. cordifolius were studied along with the plant's efficiency at treating DEG-contaminated wastewater in a constructed wetland. We found that DEG was toxic to the plants with an LD50 of 6238 mg L(-1). The plants exhibited decreased water uptake and showed wilting, chlorosis and necrosis. SEM images showed injury to the cortex tissue. In the constructed wetland, E. cordifolius plants were able to remove and degrade DEG from wastewater, decreasing the pH from 12 to 6.8 and the COD and TDS by approximately 98% and 67%, respectively, in 7 days, while accumulating Ca in the cells.     

Decolorization of basic, direct and reactive dyes by pre-treated narrow-leaved cattail (Typha angustifolia Linn.)

The efficiency of basic, direct and reactive dye removal from water by narrow-leaved cattail (NLC) powder treated with distilled water (DW-NLC), 37% formaldehyde+0.2 N sulfuric acid (FH-NLC), or 0.1 N sodium hydroxide (NaOH-NLC) at various pH levels (3, 5, 7, and 9) was tested. Desorption of the adsorbed dyes was also investigated. The type of NLC treatment and pH of the dye solution had little effect on removal of basic dyes, and efficiencies ranged from 97% to 99% over the range of pH used. Over a wide range of pH levels, all types of treated cattail powder had negative charges and probably attracted the basic dyes possessing positive charges. Efficiency of removal by the three NLC treatments ranged from 37% to 42% for direct dyes and from 22% to 54% for direct dyes at pH 7. The pH of the dye solution had substantial effects on the efficiency of removal in direct and reactive dyes. Dye removal was highest at pH 3, with 99% for a direct dye (Sirius Red Violet RL) and 96% for a reactive dye (Basilen Red M-5B). There was mutual attraction between negatively charged direct dye molecules and positively charged molecules on the surface of the FH-treated cattail. In tests of desorption of dyes from cattail in distilled water, the desorption percentage for FH-NLC after adsorbing basic, direct and reactive dyes was 6%, 10% and 35%, respectively, which indicated a chemisorption mechanism for basic and direct dyes and some physiosorption for reactive dyes.     

Phytoremediation of Bisphenol A and Total Dissolved Solids by the Mangrove Plant,Bruguiera Gymnorhiza

Bruguiera gymnorhiza, an evergreen mangrove tree, is tolerant of bisphenol A (BPA) and has potential BPA removal capability. BPA is highly toxic to plants at high concentrations, wherein they exhibit damaged symptoms such as chlorosis, necrosis, and wilting. The LD₅₀ of BPA toxicity for this plant was statistically estimated to be 39.97 mg L^–1. B. gymnorhiza can reduce COD from 15408 ± 246 to 49 ± 30 mg L^–1 by (approximately 99% reduction of the initial value) and can reduce content to levels below the industrial effluent standard of Thailand (<120 mg L^–1) within 48 days. This plant can completely remove BPA from the solution within 51 days of treatment. Polysaccharides and organic acids were found in the solution and were caused by plant response to the toxicity of BPA. In addition, B. gymnorrhiza can also reduce total dissolved solids (TDS) and salinity in real wastewater. Therefore, B. gymnorrhiza has potential for removal of BPA and TDS in contaminated in wastewater.     

Phytoextraction of Cadmium and Zinc By Sedum plumbizincicola Using Different Nitrogen Fertilizers,a Nitrification Inhibitor and a Urease Inhibitor

Cadmium (Cd) and zinc (Zn) phytoavailability and their phytoextraction by Sedum plumbizincicola using different nitrogen fertilizers, nitrification inhibitor (dicyandiamide, DCD) and urease inhibitor (N-(n-Butyl) thiophosphoric triamide, NBPT) were investigated in pot experiments where the soil was contaminated with 0.99 mg kg^?1 of Cd and 241 mg kg^?1 Zn. The soil solution pH varied between 7.30 and 8.25 during plant growth which was little affected by the type of N fertilizer. The (NH₄)₂SO₄+DCD treatment produced higher NH₄⁺?N concentrations in soil solution than the (NH₄)₂SO₄ and NaNO₃ treatment which indicated that DCD addition inhibited the nitrification process. Shoot Cd and Zn concentrations across all treatments showed ranges of 52.9–88.3 and 2691–4276 mg kg^?1, respectively. The (NH₄)₂SO₄+DCD treatment produced slightly higher but not significant Cd and Zn concentrations in the xylem sap than the NaNO₃ treatment. Plant shoots grown with NaNO₃ had higher Cd concentrations than (NH₄)₂SO₄+DCD treatment at 24.0 and 15.4 mg kg^?1, respectively. N fertilizer application had no significant effect on shoot dry biomass. Total Cd uptake in the urea+DCD treatment was higher than in the control, urea+NBPT, urea+NBPT+DCD, or urea treatments, by about 17.5, 23.3, 10.7, and 25.1%, respectively.     

A possible mechanism of Zn2+ uptake by living cells of Penicillium sp.

Metabolically-active mycelia of Penicillium sp. PT1 took up Zn²⁺ in a biphasic mode, involving an initial energy-dependent binding of Zn²⁺ to the cell surface, followed by a slower intracellular accumulation. The independent binding probably involved a simple ion exchange, as indicated by the pH decrease during the initial adsorption from 4.55 to 3.28. Intracellular accumulation probably involved polyphosphate precipitation as suggested by transmission electron microscopy     

Calcium acetate‐induced reduction of cadmium accumulation in Oryza sativa: Expression of auto‐inhibited calcium‐ATPase and cadmium transporters

• Calcium (Ca) signalling has an essential role in regulating plant responses to various abiotic stresses.
• This study applied Ca in various forms (Ca acetate and CaCl₂) and concentrations to reduce cadmium (Cd) concentration in rice and propose a possible mechanism through which Ca acts to control the Cd concentration in rice.
• The results showed that supplementation of Cd‐contaminated soil with Ca acetate reduced the Cd concentration in rice after exposure for 7 days in both hydroponic and soil conditions. The possible involvement of the auto‐inhibited Ca²⁺‐ATPase gene (ACA) might act to control the primary signal of the Cd stress response. The messages from ACA3 and ACA13 tended to up‐regulate the low‐affinity cation transporter (OsLCT1) and down‐regulate Cd uptake and the Cd translocation transporter, including the genes, natural resistance‐associated macrophage protein 5 (Nramp5) and Zn/Cd‐transporting ATPase 2 (HMA2), which resulted in a reduction in the Cd concentration in rice. After cultivation for 120 days, the application of Ca acetate into Cd‐contaminated soil inhibited Cd uptake of rice.
• Increasing the Ca acetate concentration in the soil lowered the Cd concentration in rice shoots and grains. Moreover, Ca acetate maintained rice productivity and quality whereas both aspects decreased under Cd stress.

     

Possibility to Apply Strontium Aluminate to Produce Light-Emitting Plants: Efficiency and Safety

Light-emitting plants (LEPs) provides light in areas without electricity. The phosphorescent compound was used as a lighting material for LEP development. However, using the phosphorescent compound for LEPs development required optimization and phytotoxicity evaluation. Strontium aluminate (SrAl₂O₄) is a phosphorescent compound that can glow for a long time and is easily recharged by visible light. In this study, using SrAl₂O₄ to develop LEPs was evaluated. Additionally, plant stress under SrAl₂O₄ was investigated. Metabolomic analysis can explain the possible mechanism of plants’ stress under SrAl₂O₄. After, injecting 3 mL of 5 % (w/v) SrAl₂O₄ products 1, 2, and 3 into the stem of Ipomoea aquatica, the result showed that SrAl₂O₄ products 2 and 3 caused oxidative stress. The metabolomic analysis also indicated that I. aquatica responded to SrAl₂O₄ product 1 by increasing pipecolic acid and salicylic acid, while I. aquatica injected with SrAl₂O₄ products 2 and 3 showed a decrease in salicylic acid around 0.005 and 0.061-fold, respectively, compared to control plants. and an excess accumulation of MDA around 10.00–12.00 μmol g⁻¹ FW. A 15 % concentration of SrAl₂O₄ can be used for LEPs development, enabling photoemission 18-fold for 50 min. SrAl₂O₄ product 1 has the potential to be a material for LEPs.     

EFFECT OF SILICON ON CALCIUM,PROLINE, GROWTH RATE AND SALT STRESS OF NARROW-LEAVED CATTAILS IN SYNTHETIC REACTIVE DYE WASTEWATER

Narrow-leaved cattails (Typha angustifolia L.) show higher efficiency in the removal of colour and reduction of pH, TDS, and conductivity from synthetic reactive red dye wastewater (Rw) when silicon is added to the wastewater. The efficiency of the colour removal was increased from 86% within 12 days to 93% within 9 days with the addition of silicon. Furthermore, the TDS was also decreased when adding silicon in the wastewater. In addition, calcium and proline accumulation in the plant leaf increased in response to increasing Rw concentrations in the absence of added silicon. Higher salinity was also observed with increasing Rw concentrations. Plants attempt to balance their water potential by secreting proline as an osmotic adjustment. But both calcium and proline levels decreased when silicon was added to the wastewater. This result implies that the plant uses silicon as primary element for responsibility under salt stress condition by increasing growth of plant. In addition, silicon can be used instead of calcium, resulting in decreased proline and calcium production in the plant.