Herein, we report the first example of a supramolecular carbon nanotube (CNT)-based magnetic depolluting agent for divalent metal ion (M(2+)) removal from aqueous solutions. In particular, magnetic multi-walled carbon nanotubes (m-MWCNTs) coated with poly(vinylpyridine) (PVPy) self-aggregate in aqueous solutions that contain divalent metal ions (such as Zn(2+), Cu(2+) and Pb(2+)) to form tight insoluble bundles in which the M(2+) ions remain trapped through pyridyl-M(2+)-pyridyl interactions. Magnetic filtration ultimately affords the efficient separation of the depolluted solution from the precipitated M(2+)-CNT agglomerates. Upon acid treatment, the supramolecular threads could be disassembled to afford the free CNT-polymer hybrid, thus allowing recycling of the depolluting agent. All materials and complexation/decomplexation steps were thoroughly characterised by using thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission and scanning electron microscopy (TEM and SEM, respectively). The quantification of the M(2+) residual concentrations in water was evaluated by using inductively coupled plasma optical emission spectroscopy (ICP-OES), which showed that, depending on the metal cation, this material can remove up to 99% of the contaminant.

Among synthetic thermoplastic fiber materials for reinforcement, high modulus and low shrinkage poly(ethylene terephthalate) (HMLS-PET) became the major carcass material for the low-to medium-end tire segment. Usually cords are coated with a resorcinol−formaldehyde−latex (RFL) dip to achieve acceptable power transmission. However, the low concentration of polar groups on the PET's surface requires an additional activation with costly and potentially toxic chemicals to create additional nucleophilic groups prior to RFL dipping. Here, a green enzyme based alternative to chemical HMLS-PET activation was investigated. Four different cutinase variants from Thermobif ida cellulosilytica were shown to hydrolyze HMLS-PET cords, creating new carboxylic and hydroxyl groups with distinct exoendo-wise selectivity. The highest degree of enzymatic functionalization reached a concentration of 0.51 nmol mm −2 of COOH with a release of 1.35 mM of soluble products after 72 h. The chemical treatment with 1 M NaOH released more soluble products leading up to a 10% decrease of the tensile strength while the functionalization degree achieved was only 0.21 nmol mm −2 . This clearly indicates a more endowise mode of hydrolysis for the enzymatic treatment when compared to chemical hydrolysis. Scanning electron microscopy of the fibers confirmed the aggressiveness of the chemical treatment, whereas the enzymatic approach only led to 0.7% solubilization of the polymer with no loss of mechanical properties and crystallinity changes. The newly created groups were chemically accessible and reactive in the dipping step and led after the vulcanization to a significant improvement of the adhesion between the polymer and a representative carcass rubber compound according to the peel tests.