Enhanced adsorption of Congo red on microwave synthesized layered Zn-Al double hydroxides and its adsorption behaviour using mixture of dyes from aqueous solution

The adsorption of Congo red (CR) dye on to the ZnAl-layered double hydroxides (LDHs) nanoadsorbents synthesized using conventional hydrothermal (HT) and microwave-assisted hydrothermal (MW) methods were investigated. Thorough characterization of LDHs were done by using X-ray diffraction, Fourier-transform infrared spectroscopy, BET surface area, Transmission electron microscopy and CHNS elemental analysis methods. Among the microwave synthesized LDHs, ZnAl-NO3 has shown superior adsorption capacity for Congo red (CR) in aqueous solution than its counter ZnAl-CO3 LDH which was attributed to enhanced porosity and acidic property of the ZnAl-NO3 LDH. Adsorption capacity of the LDH adsorbents has been tested using various concentrations of CR ranging from 100 to 1200 ppm in water and the monolayer adsorption capacity of ZnAl-NO3 was observed as 571.43 mg g(-1). It is important to note that adsorption studies were performed at ambient temperature and without maintaining pH of the solution. We have also studied the adsorption performance of the ZnAl-NO3-LDH for mixture of various anionic and cationic dyes in water using 25-100 ppm concentration of each dye in water. It has showed good adsorption affinity for anionic dyes over cationic dyes. In addition, the adsorption rates of CR onto ZnAI-NO3-MW are rather fast and CR adsorption equilibrium data obeys Langmuir adsorption isotherm model and kinetics data fitted to pseudo second-order kinetic model with correlation coefficients ranging from 0.998 to 0.999

DISTRIBUTION AND SEASONAL VARIATION OF HEAVY METALS IN SEDIMENTS OF MUTHUPET LAGOON, SOUTHEAST COAST OF INDIA

This study deals with seasonal variation of heavy metals in sediments of Muthupet lagoon, Southeast coast of India from September 2011 to August 2012. The bulk sediments were association with sand, silt and clay. Geo-accumulation index (lgeo) was used to quantitatively assess the influences of heavy metal pollution. Heavy metals were determined by using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and the results were compared to permissible limits of WHO/USEPA. The minimum concentration of heavy metals in all the stations were found during the post monsoon and summer seasons and the maximum concentration of heavy metals in all the stations were found during the pre-monsoon and monsoon seasons. The reason for the pollution was land drainage, irrigation through channels and municipal wastes and also the peak agricultural activities due to the release of fresh water from reservoirs. Among all the metals iron was found to be maximum in all the stations in post-monsoon and summer season followed by magnesium and manganese. Apart from these three metal, all other six metals are recorded in moderate range. The reason for the high concentration of these metals are anthropogenic activity, agriculture, aquaculture and the rivers regular in and out flow throughout the study duration in the lagoon area

Synthesis, structural and computational study, DNA binding and cytotoxic activity of Cu(II) complexes of 6- and 7-chloro-2-oxo-1,2-dihydroquinoline-3- carbaldehyde-2-furoyl-hydrazones

Three new coordination complexes of Cu(II) ions made from two hydrazone ligands, 7 -chloro2-oxo-1,2-dihydroquinoline-3-carbaldehyde-2-furoyl-hydrazone (HL1) and 6-chloro-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-2-furoyl-hydrazone (HL2) have been synthesized and fully characterized by spectroscopic techniques. Their crystal and molecular structures revealed distorted square pyramidal mononuclear complexes: [(L1)Cu(H2O)2](NO3)·3H2O, 1(NO3), [(L2)Cu(H2O)2](NO3)·2H2O·CH3OH, 2(NO3), and [(L2)Cu(NO3)[CH3OH)]·2CH3OH, 3, comprising the ligand (L1 and L2) in tridentate fashion (ONO) with two water molecules in 1+and 2+, and a single methanol molecule and a nitrate ion in 3 in their respective copper coordination spheres. EPR spectra in frozen methanol revealed the occurrence of several species arising from different coordination environments. A detailed DFT investigation on the energetics of solvents exchange (H2O, MeOH, and DMSO) and simulation of the EPR parameters showed that the exchange processes occur easily in solution. The value gz indicated the occurrence of a dimeric aggregate for 2+. The new copper complexes exhibited a noticeable antiproliferative activity with IC50 values in the micromolar range against HCT-15, H157, BxPC3, PNS-1, and A431 cell lines and they were found to be 3-fold more effective than cisplatin against pancreatic PSN-1 cell lines. Cross-resistance tests on A2780 and LoVo cancer cell lines and the corresponding multidrug or oxaliplatin resistant sublines showed that complexes 1(NO3) and 2(NO3) were equally cytotoxic to sensitive and resistant cells, thus overcoming multidrug and oxaliplatin resistance.<br/