The indiscriminate use, the alarming accumulation of plastic, and its subsequent poor well-disposal and management have generated the current environmental problem. As an environmentally friendly and effective strategy, composting processes arise like a method for waste treatment. This study explored the degradation of polyethylene terephthalate (PET) and low-density polyethylene (PE) plastic types under composting conditions for 90 days using coffee pulp as substrate into the compost. The degradation was estimated from weight variation over time, the thermal stability of the PET and PE samples was carried out using thermogravimetric analysis (TGA/DTA) whereas the chemical and morphological changes on the samples were assessed by FT-IR and SEM. The bacterial communities of composting were also investigated by 16S rRNA gene clone analysis. The results showed a partial degradation of PET and PE samples under composting conditions for the period of time considered. However, a strong adhesion effect was observed for PE samples which give place to a variation on the thermal stability of the samples. 16S RNA gene clone analysis showed that Sphingobacterium was the dominant bacteria, which is not related with the degradation of plastic material on composting. This result could be related with a reduced degradation during the composting treatment.

A geometrically tunable nanoporous system featuring enhanced active surface area by stacking of spheres in cylindrical pores is fabricated. Highly ordered arrays of straight, constricted pores are obtained by anodization of metallic aluminum. Polystyrene (PS) spheres are assembled inside the pores by flowing their suspension through the porous membrane, whereas the construction serves as a filter. After surface functionalization with a noble metal catalyst, these model electrocatalysis systems exhibit functional properties (capacitance in electrochemical impedance spectroscopy) that mirror their geometric parameters. A systematic investigation of the system's geometry as it depends on the surface chemistry of the pores, on the one hand, and the physical parameters of the infiltration procedure, on the other hand, shows that mechanical stacking prevails over surface chemical interactions to determine the stacking density. The highest values of surface area are obtained when PS spheres are put in contact with HfO2 followed by ZnO according to adsorption measurements. Surface derivatization with organic layers does not improve stacking any further. However, choosing the proper concentration of PS spheres and flow rate are crucial for obtaining densely packed sphere assemblies without clogging of the pore entrance.