Biosynthesis of lead nanoparticles by the aquatic water fern, Salvinia minima Baker, when exposed to high lead concentration

Kinetic study for removal of cationic hexamethyl pararosaniline chloride dye using phytoremediation

The present investigation provides a kinetic study for the removal of hexamethyl pararosaniline chloride, a hazardous dye, by phytoremediation using a water plant. It reveals Salvinia molesta has a phytoremediation tendency. The ability of Salvinia molesta to remove crystal violet (CV) dye is investigated with kinetic study in this research. Phytoremediation is done for different concentrations of hexamethyl pararosaniline chloride with varying pH and weight of Salvinia molesta Mitchell. About 88% of hexamethyl pararosaniline chloride has been decolourised from 50 mg L-1 solution at pH of 6 with 4 g of Salvinia molesta Mitchell. The results obtained for hexamethyl pararosaniline chloride removal at pH of 6 are studied for pseudo-first order, pseudo-second order and Elovich kinetics. The resulting curve for removal of hexamethyl pararosaniline chloride indicates that phytoremediation process follows pseudo-second order kinetics with correlation value R2 ≥ 0.985. The Salvinia molesta used at pH 6 has been reused and the decolourisation has been achieved at about 84% for 50 mg L-1 solution of CV dye. The FTIR results reveal the phytoextraction of CV in the roots by interaction of functional groups. From the experimental results, Salvinia molesta Mitchell can be used to treat textile wastewater and wet land.

Kinetic Evaluation for Removal of an Anionic Diazo Direct Red 28 by Using Phytoremediation Potential of Salvinia molesta Mitchell

The dye removal using phytoremediation has demonstrated its potential to degrade many recalcitrant dyes. The kinetic investigations for phytoremediation ability of Salvinia molesta Mitchell (S. molesta) were evaluated for Direct Red 28 (DR28) dye in the present research work. The potential of S. molesta was analysed at different pH and different initial dye concentrations. About 90 % of dye decolorization was achieved for 50 mg L^-1 dye solution with 4 g of S. molesta plant at pH 6.5. The experimental results were evaluated with pseudo-first, pseudo-second and Elovich kinetic models. The validation indicated the most suitable curve with Pseudo-second order having the correlation value R² ≥ 0.99. FTIR studies supported the phytoextraction of DR28 through functional group interaction between plant hairy roots and dye molecules. The results of the present studies suggests that S. molesta can be utilized for remediation of water bodies and wetlands contaminated with dye wastewater in natural conditions.

Interactions of Coated-Gold Engineered Nanoparticles with Aquatic Higher Plant Salvinia minima Baker

The study investigated the interactions of coated-gold engineered nanoparticles (nAu) with the aquatic higher plant Salvinia minima Baker in 2,7, and 14 d. Herein, the nAu concentration of 1000 µg/L was used; as in lower concentrations, analytical limitations persisted but >1000 µg/L were deemed too high and unlikely to be present in the environment. Exposure of S. minima to 1000 µg/L of citrate (cit)- and branched polyethyleneimine (BPEI)-coated nAu (5, 20, and 40 nm) in 10% Hoagland’s medium (10 HM) had marginal effect on biomass and growth rate irrespective of nAu size, coating type, or exposure duration. Further, results demonstrated that nAu were adsorbed on the plants’ roots irrespective of their size or coating variant; however, no evidence of internalization was apparent, and this was attributed to high agglomeration of nAu in 10 HM. Hence, adsorption was concluded as the basic mechanism of nAu accumulation by S. minima. Overall, the long-term exposure of S. minima to nAu did not inhibit plant biomass and growth rate but agglomerates on plant roots may block cell wall pores, and, in turn, alter uptake of essential macronutrients in plants, thus potentially affecting the overall ecological function.

Biological Nanofactories: Using Living Forms for Metal Nanoparticle Synthesis

Metal nanoparticles are nanosized entities with dimensions of 1-100 nm that are increasingly in demand due to applications in diverse fields like electronics, sensing, environmental remediation, oil recovery and drug delivery. Metal nanoparticles possess large surface energy and properties different from bulk materials due to their small size, large surface area with free dangling bonds and higher reactivity. High cost and pernicious effects associated with the chemical and physical methods of nanoparticle synthesis are gradually paving the way for biological methods due to their eco-friendly nature. Considering the vast potentiality of microbes and plants as sources, biological synthesis can serve as a green technique for the synthesis of nanoparticles as an alternative to conventional methods. A number of reviews are available on green synthesis of nanoparticles but few have focused on covering the entire biological agents in this process. Therefore present paper describes the use of various living organisms like bacteria, fungi, algae, bryophytes and tracheophytes in the biological synthesis of metal nanoparticles, the mechanisms involved and the advantages associated therein.

Colocalization of low-methylesterified pectins and Pb deposits in the apoplast of aspen roots exposed to lead

Low-methylesterified homogalacturonans have been suggested to play a role in the binding and immobilization of Pb in CW. Using root apices of hybrid aspen, a plant with a high phytoremediation potential, as a model, we demonstrated that the in situ distribution pattern of low-methylesterified homogalacturonan, pectin epitope (JIM5-P), reflects the pattern of Pb occurrence. The region which indicated high JIM5-P level corresponded with "Pb accumulation zone". Moreover, JIM5-P was especially abundant in cell junctions, CWs lining the intercellular spaces and the corners of intercellular spaces indicating the highest accumulation of Pb. Furthermore, JIM5-P and Pb commonly co-localized. The observations indicate that low-methylesterified homogalacturonan is the CW polymer that determines the capacity of CW for Pb sequestration. Our results suggest a promising directions for CW modification for enhancing the efficiency of plant roots in Pb accumulation, an important aspect in the phytoremediation of soils contaminated with trace metals.