Adsorption of nitrobenzene and orthochlorophenol on dimethyl ditallowyl montmorillonite: A microstructural and thermodynamic study

The adsorption of two different organic aromatic pollutants (nitrobenzene and orthochlorophenol) onto a commercial organoclay (dimethyl ditallowyl ammonium montmorillonite) was investigated. Adsorption was investigated over a wide range of concentrations, corresponding to 0.0016–0.24 mol/L for nitrobenzene and 0.002–0.29 mol/L for orthochlorophenol. The uptake of nitrobenzene and orthochlorophenol by the organobentonite was demonstrated to determined different processes: in the former case a partition process seemed to be favoured, while in the latter a combination of partition and adsorption onto specific sites appeared to be more reasonable

Long-term leaching test of organo-contaminated cement-clay pastes

The aim of the present work is to investigate the effect of a prolonged leaching test (more than a year) on the microstructure of solidified cementitiouswasteforms. A set of four different cement-based monoliths (Ap, Bp, Cp and Dp) was prepared, and for each series an uncontaminated sample was prepared as reference (A–D). An organoclaywas added in all pastes as pre-sorbent material for the pollutant; a model liquid organic pollutant, 2-chloroaniline (2-CA), was added only in the contaminated ones and different types of admixtures, chosen among those typically employed in the concrete mix-design,were used. After the first 28 days of curing, all the monoliths, contaminated and uncontaminated, underwent a dynamic leach testing (DLT) for more than 1 year in deionized water

Supporting a transition towards sustainable circular economy: sensitivity analysis for the interpretation of LCA for the recovery of electric and electronic waste

Purpose The interpretation in life cycle assessment (LCA) is a fundamental step for ensuring the robustness of the overall study. Moving forwards towards more circular economy requires that different waste management options are systematically scrutinized to assess the environmental impacts and benefit associated to them. The present work aims at illustrating how a sensitivity analysis could be applied to the impact assessment step supporting the interpretation of a LCA study applied to a waste management system that includes material recovering. The focus is on toxicity-related and resource-related potential impacts as they are considered among the most critical ones, which may affect the way the final benefit from material recovery is evaluated. Material and methods Possible alternatives in terms of impact assessment assumptions and modelling are tested by performing a sensitivity analysis on a case study on electric and electronic waste. For the toxicity-related impact categories, first, a sensitivity analysis is performed using different sets of characterization factors for metals aiming at identifying how they are affecting final results. Then, an analysis of the relative contribution of long term emissions in upstream processes is carried out aiming at unveiling critical issues associated to their inclusion or exclusion. For the resource depletion impact category, a sensitivity analysis has been performed adopting different sets of characterization factors based on existing models for minerals and metals as well as recently proposed sets accounting to critical raw materials. Results and discussion The indicator of the eco-toxicity impact category obtained by applying the updated characterization factors is about three times higher than the corresponding obtained by the USEtox model. The long term emissions result responsible for the major part of all the toxicity impact indicators. Moreover, for the eco-toxicity indicator, excluding the long-term emissions changes the total results from being negative into positive. The sensitivity analysis for the resource depletion impact category shows that all the models applied result in a total avoided impact. A quantitative comparison among all the results is not possible as the different models use different unit of measures. Conclusions The importance of conducting an extensive sensitivity analysis is shown. The application of LCA is crucial for assessing avoided impacts and uncovers potential impacts due to recycling. However, contrasting results may stem from the application of different assumptions and models for characterization. A robust interpretation of the results should be based on systematic assessment of the differences highlighted by the sensitivity, as guidance for delving into further analysis of the drivers of impacts and / or to steer eco-innovation to reduce those impacts.JRC.D.1-Bio-econom