In this study, coconut shells were converted into biochar via pyrolysis and chemically modified an acid-base treatment to enrich its adsorption capabilities. Batch experiments carried out analyze the potential of shell (MCSC) or removal chromium, nickel, copper from aqueous solution. The chemical modification increased surface area MCSC 185.712 m 2 /g. study using resulted in 99% copper, 95% (n...

Supercritical fluid extraction (SFE) provides an environmentally green technique to decontaminate chromium species from solid matrices using supercritical fluid carbon dioxide (ScCO2). Methanol and a small amount of water were found to significantly improve the extraction efficiency. The fluorinated chelating agent lithium bis(trifluoroethyl)-dithiocarbamate (LiFDDC) was effective in removing C...

Fused yttrium-alumoborate glasses doped with ytterbium, silicon, chromium, and sodium were synthesized. The influence of the matrix on "spectroscopic behavior" chromium ions efficiency their sensitization Yb3+ luminescence was established by spectral-luminescence EPR-studies. It found that (1) in alkali-free is mainly oxidation degree Cr(III) an appreciable admixture Cr(IV) Cr(V), (2) partial r...

A study of electronic and magnetic properties of an octametallic chromium-based homonuclear molecule Cr8F8(CO2 −C(CH3)3)16 is presented, using density functional theory (DFT) approach and linearized augmented plane wave (LAPW) method with Perdew, Burke and Ernzerhof (PBE) and Becke 3-term correlation (B3LYP) functionals. The exchange coupling parameters between transition metals ions are extrac...

The electrokinetic technique is an emerging technology presently tested in situ to remove dissolved heavy metals from contaminated groundwater. There is a growing interest for using this system to cleanse clayey soil contaminated by toxic metallic ions. Currently, there are very few available non-destructive treatment methods that could be successfully applied in situ on low permeable type of s...

Husk of tur dal (Cajanus cajan) was investigated as a new biosorbent for the removal of Fe (III) and Cr (VI) ions from aqueous solutions. Parameters like agitation time, adsorbent dosage and pH were studied at different initial Fe (III) and Cr (VI) concentrations. The biosorptive capacity of the Tur dal husk was dependent on the pH of the chromium and iron solution, with pH 2 and 2.5 respective...

Iron(II) in buffer medium and in presence of oxalate has been proposed as a new electron transfer reagent or reducing agent for the selective determination of chromium(VI) in presence of several other metal ions such as Mo(VI), U(VI), V(IV) etc. The method consists in taking a chromium(VI) solution [ containing 3-11mg of Cr] into a buffer medium of pH ~ 4.05.2 containing about 0.040.10M potassi...

In this paper we report the spectroscopic data for samples of 0.031% iron, 0.017% nickel, 0.01% chromium and 0.017% cobalt (molar) doped gallium lanthanum sulphide (GLS) glass. Photoluminescence (PL) with a full width half maximum (FWHM) of around 500 nm and peaking between 1120 nm and 1460 nm is observed when excited using wavelengths of 850 nm and 1064 nm. The emission lifetime for nickel-dop...

Experimental details of atom probe field ion microscopy (APFIM) of a Ni-16Cr-9Fe alloy are presented. In particular, studies concerning analysis of intergranular carbides and borides and segregation to grain boundaries are described. It was found that NiZ3B6 precipitates are very sensitive to preferential field evaporation, which necessitates optimization of the analysis conditions. In the FIM ...