Indium is increasingly used in electronic devices, from which it can be mobilized towards environmental compartments. Speciation of In in waters is important for its direct ecotoxicological effects, as well as for the fate of this element in the environment (e.g. fluxes from or towards sediments). Free indium concentrations in the environment can be extremely low due to hydrolysis, especially important in trivalent cations, to precipitation and to complexation with different ligands. In this work, the free indium concentration (which is a toxicologically and geochemically relevant fraction) in aqueous solutions at pH3 has been measured with an adapted version of the electroanalytical technique AGNES (Absence of Gradients and Nernstian Equilibrium Stripping). Speciation measurements in mixtures of indium with the ligands NTA (nitrilotriacetic acid) and oxalate indicate that the values of their stability constants in the NIST46.6 database are less adequate than those published in some more recent literature. The extraordinary lability and mobility of In-oxalate complexes allow the measuring of free indium concentrations below nmol/L in just 25s of deposition time.

The vast industrial and consumer application of indium (solar cells, displays, etc.) risks its eventual leakage to the environment. Given the relevant role of speciation on the ecotoxicological effects of a certain total amount of indium, it is crucial to develop proper techniques to determine free concentrations of indium. The electroanalytical technique AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) has already proved useful in such a goal. However, the optimization of suitable deposition times in some conditions might be laborious. This work presents a new strategy, based on the technique ADLC (Accumulation under Diffusion Limited Conditions), to determine lability degrees, which apart from their intrinsic physicochemical interest -by comparing reaction kinetics with diffusion rates-, provide useful guidelines for AGNES deposition times. The suggested novel methodology is illustrated with: i) the computation of lability degrees of indium-oxalate complexes (unreported up to date) and ii) measuring free concentration of indium (for the first time as low as pmol L -1 ) in precipitated solutions (i.e. containing precipitated indium hydroxide in the electrochemical cell). The method takes advantage of the fact that the addition of a suitable concentration of oxalate does not change the free indium concentration (which is buffered due to the existing precipitate at a fix pH), but creates a large amount of published in Journal of Electroanalytical Chemistry 847 (2019) 113185 2/38 labile and mobile indium complexes that contribute to the desired accumulation at very large gains (preconcentration factors). Results confirm the validity of the solubility product of indium hydroxide reported in the database NIST 46.7

This study aims to identify and prioritize indicators of green Management in the Energy and Waste fields in Erfan hospital of Tehran , Iran. By examining the relativle books and by using Delphi technique and AHP (Analytic Hierarchy Process) model , as well as green management guide. After expert consensus on the suitability for adopted decision making criteria, defined criteria for prioritization of green management indicators were introduced in three major sectors (productivity, energy, waste control and disposal). The prioritization of desired criteria was done using AHP model and EC (Expert Choice) application. The most important among green management criteria for productivity , energy as well as waste control and disposal were optimal use of resources , energy conservation and waste separation , respectively. Indicators of resource efficiency, sustainable development and energy conservation are factors in the emergence of management as a priority to third.