Endosulfan, an organochlorine pesticide, is known for its toxicity and ability to accumulate in the environment. In India endosulfan was banned only in 2011 and hence toxic residues are still persistent in the environment. The abilities of three plant species Chittaratha (Alpinia calcarata), Tulsi (Ocimum sanctum), and Lemongrass (Cymbopogon citratus) to remove endosulfan from soil in the absence and presence of zerovalent iron nanoparticles (nZVIs) (1000 mg/Kg of soil), i.e., by phytoremediation and nano-phytoremediation, were determined. Extracted soil samples from the experimental plot were analyzed using Gas Chromatograph with Electron Capture Detector (GC-ECD) and final dehalogenated product was confirmed by Mass Spectrometer (MS). A. calcarata had the best efficiency compared to the other two plant species and the efficiency decreased in the order A. calcarata > O. sanctum> C. citrates. The initial endosulfan removal rate was high (82% was removed within 7 days) when nano phytoremediation experiments were conducted with A. calcarata but then gradually decreased, probably because the activity of nZVI decreased over time. The nZVI endosulfan degradation mechanism appears to involve hydrogenolysis and sequential dehalogenation which was confirmed by GC-MS analysis. Only small amounts of endosulfan were accumulated in the plants because the added nZVIs might have promoted the reductive dechlorination of endosulfan.

This study was conducted to measure the impact of a municipal solid waste landfill on groundwater quality around Njelianparamba, a solid waste dumping site in Kozhikode district, Kerala state, India. One of the major problems associated with dumping of municipal solid waste landfill is the release of leachate and its impact on surrounding groundwater. In this study, physico-chemical and bacteriological parameters of groundwater samples collected from the region surrounding the leachate area during the pre-and post-monsoon seasons were analysed. The majority of the groundwater samples contained contaminants at a level beyond the permissible limit set by the Bureau of Indian Standards for drinking water quality. The Geographic Information System software of the Environmental Systems Research Institute, (USA) ArcMap 10.1 was used to prepare spatial distribution maps of different parameters and Leachate Pollution Index and Water Quality Index in the study area were applied to assess the overall quality of groundwater. Characterisation of leachate and groundwater samples revealed that, water in the domestic wells has been deteriorated in response to the percolation of leachate. Additionally spatial and correlation analysis revealed that contamination was present maximum within 300 m radius around the landfill site.

An integrated photocatalytic adsorbent system prepared from bentonite clay and titanium dioxide was used for the adsorption/degradation of model organic pollutants and adsorption of heavy metals from industrial wastewater. The...

The performance of electrically stimulated phytoremediation in the removal of lead, cadmium and copper was assessed in this study. A combination of phyto and electro remediation was attempted in this study for the remediation of the metals from water. Three tanks were set up with different operating conditions for this experiment: control A (only phytoremediation system), control B (only electro remediation) and treatment (combination of phyto and electro remediation). The electrically enhanced phytoremediation system and electro remediation system were operated 2h/day at voltages of 4V for 25 days continuously. In this experiment, the Eichhornia crassipes, an able phyto-remediator exhibited efficient and fast removal of heavy metals from synthetic solution in electro assisted phytoremediation system. The electrically enhanced phytoremediation using aluminum sheet electrodes showed better and effective removal of Cd, Pb and Cu than aluminum rod electrodes. A more favorable and moderate increase of pH was noticed in electrically stimulated phytoremediation system. Eichhornia crassipes has a tremendous potential to reduce the maximum amount of cadmium (within 15 days), lead (within 15 days) and copper (within 10 days) under electrically stimulated condition. Under electrified condition, maximum amount of Cd and Cu was accumulated in the aerial parts of Eichhornia crassipes but maximum concentration of Pb was attained by roots. This indicates the high heavy metal accumulation capacity of Eichhornia crassipes under electrified conditions. The results showed that 4V voltage is probably suitable to stimulate the Eichhornia crassipes to synthesize more chlorophyll and voltage can improve the growth and ability to resist adverse circumstances by promoting chlorophyll synthesis. Eichhornia crassipes stimulated by an electric field has grown better and assimilated more metal. Bioconcentration factor (BCF) an index of hyperaccumulation, indicates that electrically stimulated Eichhornia crassipes is a good hyper accumulator of Cd (BCF = 1118.18) and Cu (BCF = 1152.47) and a moderate accumulator of Pb (BCF = 932.26). Translocation ability (TA) ratio indicates that Eichhornia crassipes have the ability to translocate more amounts of Pb, Cd and Cu to its upper portion under electrified condition. The results imply that the electro-phytoremediation technique seems to be promising in the treatment of wastewater contaminated with heavy metals.

An increased discharge of nitrates to the natural water resources was observed across the globe due to various anthropogenic activities resulting in environmental pollution and associated harmful effects. In the present work, sol-gel-derived functional nanocomposites based on silver (Ag) doped titanium dioxide (TiO 2 ) coated chitosan nanocomposites were successfully synthesized in the form of beads and their application for the removal of nitrates from the water was studied. The synthesized nanocomposite beads were further characterized for their structural, textural, and morphological features using X-ray Diffraction Analysis, Fourier Transform Infrared Spectroscopy, UV-Visible Spectroscopy, BET Surface Area analysis, Scanning Electron Microscopy, and Transmission Electron Microscopy. A uniform coating of doped titania species on the chitosan porous structure was achieved through electrostatic interaction.Adsorption/ photocatalytic reduction of nitrates was further monitored by measuring the concentration of nitrate ions in the model contaminated water in the presence of functional nanocomposite beads when subjected to an adsorption study under dark conditions and photocatalytic study under UV/sunlight for a de nite time. Drying conditions of the nanocomposite beads were found to have a signi cant effect on the adsorption cum photocatalysis e ciencies of the nanocomposite. The freeze-dried chitosan-titania nanocomposite beads containing 0.5 mol% Ag exhibited an adsorption e ciency of ~ 43.5% (under dark for 30 min) and photocatalytic reduction capability of ~ 95% (under sunlight for 2 hours), whereas the adsorption and photocatalytic e ciencies were 40% (under dark for 30 min) and 70% (under UV light for 2 hours) respectively, in the case of oven-dried nanocomposite beads, towards the removal of nitrate ions in an aqueous solution. Continuous ow adsorption cum photocatalytic study using the oven-dried nanocomposite beads was carried out further with the help of an experimental setup fabricated in-house and under varying experimental conditions such as ow rate, bed height, and concentration of feed solution. A nitrate removal e ciency of 87.6% and an adsorption capacity of 7.9 mgg − 1 were obtained for the nanocomposite beads in the continuous ow adsorption cum photocatalysis experiment for up to 8 hours when using an inlet concentration of 100 ppm, bed height 12 cm and ow rate 5.0 mlmin − 1 . A representative xed-bed column adsorption experiment using a real groundwater sample collected from the Palakkad District of Kerala was also performed using the oven-dried functional nanocomposite beads that show promising results for nitrate removal (85.9% e ciency) along with a signi cant removal rate for the other anions as well. Thus, the adsorption cum photocatalytic nitrate reduction ability of the synthesized functional material makes them suitable for the e cient removal of nitrates from water/wastewater through an integrated nanocomposite approach.