Recycled carbon (RC) materials made functional: An efficient heterogeneous Mn-RC catalyst

Fabrication of Pt-Loaded Catalysts Supported on the Functionalized Pyrolytic Activated Carbon Derived from Waste Tires for the High Performance Dehydrogenation of Methylcyclohexane and Hydrogen Production

The pyrolytic activated carbon derived from waste tires (PTC) was functionalized to fabricate the high performance of Pt-based catalysts in the dehydrogenation of methylcyclohexane and hydrogen production. Structural characterizations evidenced that the modification partially influenced the surface area, the pore structure, and the oxygen-containing functional groups of the supports. The techniques of CO pulse, transmission electron microscopy, and hydrogen temperature-programmed reduction were utilized to investigate the dispersion degrees and particle sizes of the active component Pt, and its interaction with the various functionalized supports, respectively. The results manifested that Pt particles loaded on the functionalized PTC-S had the largest dispersion degree and the smallest size among those loaded on PTC and other functionalized PTC (i.e., PTC-K and PTC-NH). Finally, the Pt-based catalysts were successfully applied in the dehydrogenation reaction of methylcyclohexane to yield hydrogen. The results revealed that the Pt catalyst over the functional PTC-S support exhibited a more excellent conversion of methylcyclohexane (84.3%) and a higher hydrogen evolution rate (991.5 mmol/gPt/min) than the other resulting Pt-based catalysts.

Natural Mn-todorokite as an efficient and green azo dye-degradation catalyst

A natural Mn mineral, i.e., todorokite [(Ca,Na,K)_X(Mn⁴⁺,Mn³⁺)₆O₁₂·3.5H₂O], has been collected in the Apulia region, south of Italy, and evaluated as an oxidation catalyst for the degradation of methyl orange (MO) dye. This Mn-todorokite mineral has been firstly characterized by X-ray diffraction, wavelength-dispersive X-ray fluorescence, BET, scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and thermogravimetry. Catalytic dye-degradation data show that this Mn-todorokite can operate under strongly oxidizing potentials (E_h > + 400 mV) vs. standard hydrogen electrode performing fast MO degradation (t_1/2 < 1 min). A detailed study using electron paramagnetic resonance spectroscopy revealed that, under oxidative conditions (E_h > + 450 mV), the active Mn centers of todorokite evolve rapidly through Mn³⁺/Mn⁴⁺ states and this is correlated with the fast catalytic degradation of MO. These results suggest Mn-todorokite mineral as an efficient, low-cost, and green catalyst which can be used for industrial and environmental purposes.

Rubber industry

Following chapter presents short introductory description of rubber and rubber industry. The main problem of rubber industry is the way of the usage of spent tires. Furthermore very important group of problems arise considering the metal and nonmetal additives which are significant component of the vulcanized rubber. The key attention is dedicated to typical ways of rubber usage in utilization and recovery of metals from spent rubber materials concentrating specifically on used tires processing. The method of recovery of rare metals from rubber tires was described. The rubber debris finds widest use in the field of waste metal solutions processing. The environmental pollution caused by metals poses serious threat to humans. Several applications of the use of waste rubber debris to remove metals from environmental waters were described. Moreover, the agriculture usage of waste tire rubber debris is described, presenting systems where the rubber material can be useful as a soil replacement.

Recycled-tire pyrolytic carbon made functional: A high-arsenite [As(III)] uptake material PyrC350®

A novel material, PyrC₃₅₀^®, has been developed from pyrolytic-tire char (PyrC), as an efficient low-cost Arsenite [As(III)] adsorbent from water. PyrC₃₅₀^® achieves 31mgg^-1 As(III) uptake, that remains unaltered at pH=4-8.5. A theoretical Surface Complexation Model has been developed that explains the adsorption mechanism, showing that in situ formed Fe₃C, ZnS particles act cooperatively with the carbon matrix for As(III) adsorption. Addressing the key-issue of cost-effectiveness, we provide a comparison of As(III)-uptake effectiveness in conjunction with a cost analysis, showing that PyrC₃₅₀^® stands in the top of [effectiveness/cost] vs. existing carbon-based, low-cost materials.