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The adsorption of the herbicide atrazine in packed beds filled with solids modelling soil components,
(silica and humic acid), was studied at conditions simulating the adsorption of atrazine in cultivated
soils. The choice of only two constituents of soil in the experimental study was based on the
assumption that these two compounds contribute significantly to the adsorption of herbicides in soil
relative to others, like alumina, calcium carbonate, etc. Packed beds were filled with inorganic
material (silica gel grains) and solid organic compounds (humic acid). Adsorption data were fitted to
the Freundlich isotherm. The presence of humic acid, even in small quantities, increases
considerably the amount of adsorbed atrazine. Increasing humic acid content in the packed beds,
the amount of adsorbed atrazine increased. Reversibility tests showed that the adsorption of
atrazine was reversible. Two steps for adsorption and desorption were observed. The first fast step
is attributed to the physical adsorption on the free adsorption sites of the substrates washed by the
solution, while the second slow step is attributed to the diffusion of the molecules of atrazine within
the structure of the silica and of the humic acid. Study of the hydrodynamics of atrazine containing
solutions flow in the packed beds filled with silica and humic acid showed that the morphology of
insoluble humic acid upon hydration changed its shape resulting in its transport through the bed and
clogging of the narrow pores of the medium. As a result the packed bed permeability was reduced
by 99%.

The stringent new regulations to lower sulfur content in fossil fuels require new economic and
efficient methods for desulfurization of recalcitrant organic sulfur. Hydrodesulfurization of such
compounds is very costly and requires high operating temperature and pressure. Adsorption is a
non-invasive approach that can specifically remove sulfur from refractory hydrocarbons under mild
conditions and it can be potentially used in industrial desulfurization. Intensive research has been
conducted in materials development to increase their desulfurization activity; however, even the
highest activity obtained is still insufficient to fulfil the industrial requirements. To improve the
adsorption capacity and sorbent regeneration, more work is needed in areas such as increasing
specific desulfurization activity, hydrocarbon phase tolerance, sulfur removal at higher temperature,
and development of new porous substrates for desulfurization of a broader range of sulfur
compounds. This work comprehensively describes the adsorption of organo-sulfur compounds
present in liquid fuels on metal-organic framework (MOF) compounds. It has been demonstrated that
the extent of dibenzothiophene (DBT) adsorption at temperatures close to ambient (304 K) is much
higher on MOF systems than on the benchmarked Y-type zeolite and activated carbons. In addition, the
DBT adsorption capacity depends strongly on the MOF type as illustrated by the much higher extent of
adsorption observed on the Cu-(C300) and Al-containing (A100) MOF systems than on the Fe-containing
(F300) MOF counterpart.

Activated carbon (AC) is currently being used to treat polychlorinated biphenyl (PCB) contaminated
field sediment. In the presence of sediment, the sorption capacity of AC for PCBs can be reduced. In
this study, sorption attenuation of AC is investigated using previously published data from 5
sampling sites where reductions in aqueous concentrations caused by AC amendment have been
reported. AC-water partitioning coefficients (KAC_clean_water) were determined at a relevant PCB
concentration in clean water using polyoxymethylene (POM) passive samplers. Logarithmic ACwater
partitioning coefficient values ranged from 7.39 to 9.59 for trichlorinated to pentachlorinated
congeners. These AC-water partitioning coefficients were used in a numerical model to predict
expected reductions in aqueous concentrations. Results reveal an overprediction of actual
reductions by a median factor ranging from 2.5 to 5.6. To obtain an estimate of AC sorption
attenuation, an AC-water partitioning coefficient more representative of sediment conditions
(KAC_apparent) was fitted via the model based on the observed reductions in aqueous concentrations.
On average, median KAC_apparent values of individual PCB congeners were smaller than KAC_clean_water
values by 1.08 log units, or a factor of 12, with corrections ranging from 0.1 to 2.3 log units. The
main controls on the reduction in sorption of PCBs to AC are PCB physico-chemical properties and
AC amendment variables. Generally AC sorption attenuation increased with PCB hydrophobicity and
decreased with increasing AC-sediment contact time and AC dose.

Composting of organic solid wastes is gaining in importance worldwide, in the frame of integrated
municipal solid waste management and, in particular, the diversion of biodegradables from
landfilling. At the post-consumer stage, this can be achieved by composting practices ranging from
large-scale facilities to home (or yard) composting. Increasing costs for final disposal of MSW also
point towards the use of composting technology as an alternative. This paper presents some results
and conclusions from various small-scale composting activities implemented in Hanoi and Manila
under different socio-economic settings, as well as a case study on a larger-scale composting
scheme in the Prefecture of Pieria, Greece in the frame of a 2-year joint research project. It focuses
on recommendations towards the Asian partners on how to improve their composting processes, on
the basis of reviewing and assessing current composting practices in Vietnam and the Philippines,
as well as some remarks on cost parameters for the Hellenic case study.