Waste-derived Material Research Articles

High performance waste-derived filler/carbon black reinforced guayule natural rubber composites

Guayule rubber (GNR) is an alternative source of natural rubber that does not crossreact with Type I latex allergy because it does not contain any proteins which can be recognized by antibodies raised against Hevea brasiliensis allergens. To advance the commercialization of this elastomer and diversify sources of natural rubber, efficient reinforcement of GNR is required to match the physical properties of vulcanized materials made from H. brasiliensise natural rubber in specific products. Superior or comparable reinforcement to that of carbon black N330, was achieved by partial replacement of carbon black with 5 and 10 phr of waste-derived material. Out of several waste-derived fillers tested, micro sized eggshells showed remarkable reinforcing potential for GNR. Hybrid carbon black/micro sized eggshells/GNR composites (up to 20 phr micro sized eggshells), had increased tensile strength, and elongation at break, while maintaining similar values of 300% modulus and hardness to those achieved by carbon black/GNR composites. Hierarchical cluster analysis partitioned the data into six groups of composites having statistically similar properties within each group. Composites containing 5–20 phr of micro sized eggshells were clustered in a separate group due to their unique combination of high tensile strength and flexibility. The superior reinforcement may reflect a combined synergistic reinforcing effect of carbon black particles, which possess a strong polymer-filler interaction, with the formation of a unique network between the GNR and the waste-derived materials, not attained with H. brasiliensis natural rubber.

Removal of cadmium ions from wastewater using innovative electronic waste-derived material

Cadmium is a highly toxic heavy metal even at a trace level. In this study, a novel material derived from waste PCBs has been applied as an adsorbent to remove cadmium ions from aqueous solutions. The effects of various factors including contact time, initial cadmium ion concentration, pH and adsorbent dosage have been evaluated. The maximum uptake capacity of the newly derived material for cadmium ions has reached 2.1mmol/g at an initial pH 4. This value shows that this material can effectively remove cadmium ions from effluent. The equilibrium isotherm has been analyzed using several isotherm equations and is best described by the Redlich–Peterson model. Furthermore, different commercial adsorbent resins have been studied for comparison purposes. The results further confirm that this activated material is highly competitive with its commercial counterparts.

Recovery of useful hydrocarbons from oil palm waste using ZrO 2 supporting FeOOH catalyst

The possibility of recovering useful hydrocarbons from oil palm waste derived lignocellulose (palm shell oil) using steam tolerant catalysts was investigated. The examined catalysts were rare earth metal exchanged Y-type (REY) zeolites, nickel supporting REY zeolites and FeOOH catalysts. It was found that palm shell oil could be converted to a mixture which mainly contains phenol, acetone and butanone without hardly generating solid residues when a FeOOH catalyst was used. Therefore, by catalytic reaction, this waste-derived material may become a new and abundant chemical source. The catalytic activity of this FeOOH catalyst can be enhanced by supporting ZrO 2 on it. It was found that oxygen transfer during reaction occurs mainly from H 2O to the products, not from the oxygen of the catalyst. It is assumed that the supported ZrO 2 plays a role of the decomposition of H 2O adsorbed on the catalyst, yielding active hydrogen and oxygen species, which is also supported by the results of thermal desorption spectra and Mössbauer spectroscopy analysis of the catalyst.