Attempts to use waster rubber powder as an adsorbent of pollutants in wastewater treatment applications is an environmentally friendly, efficient and novel method, especially in the tire industry wastewater treatment process. This study evaluated the efficiency of waste tire rubber powder in adsorbing the tire industry wastewater. The rubber and The wastewater were prepared from Kavir Qom Co. and Artawheel tire Co., respectively. Comparison of UV-vis spectrophotometer results of the nontreated wastewater with the wastewater data after adsorption under various thermal and temporal conditions indicated that the tire powder adsorbent has the necessary efficiency for treating the tire industry wastewater. Examination of data with pseudo-first- and second-order kinetic models also confirmed the adsorbent’s efficiency and showed that the second-order kinetic model had a good correspondence with the obtained results.

Severity of energy crisis is so acute in our society whereas environmental degradation is another challenging issue. Combining these two, environmental pollution can be eradicated permanently which is the burning issue for many countries of the world. Nowadays recycling of tire waste can be a dependable solution for minimizing energy crisis and environmental pollution as well as energy crisis. Similar to bio resources these wastes tire have the features of manufacturing energy by altered thermochemical conversion process. In the previous time waste tire pyrolysis was conducted without catalyst whereas the present pyrolysis with catalyst. The objectives were investigating the effect on oil extraction and the composition of derivative oil from tire waste in presence of catalyst. The effect of pyrolysis heating rate, temperature, operating time, catalyst/tire ratio (CT ratio) and sample size etc. on yield were also investigated. The pyrolysis process was carried out in temperature range of 300 to 600º C. The most favorable pyrolytic oil attained was 42. 0% (wt) for without catalyst as well as 36. 67% (wt) for catalytic pyrolysis at 450º C. Characterization of physical properties of the resulting pyrolytic oil showed that increase in pyrolysis temperature and CT ratio resulted in higher yield of gas at the expense of oil. When CT ratio is increased from 0. 13 to 0. 30, the gas yield is increased from 13. 33 to 15. 33% (wt) and oil yield decreased from 36. 67 to 28. 0% (wt) at temperature of 450oC. High CT ratio favored an increase in the concentration of light naphtha in the pyrolytic oil. A yield of 97% (wt) is obtained from of the pyrolytic oil at 450oC with CT ratio 0. 3 by fractional distillation below 350oC. It could be concluded that after proper treatment these oil can be used as substitute of alternative fuel or chemical feedstock to naphtha.

The results on testing application of ground tire rubber (GTR), as potential filler for butyl rubber, are presented. The GTR content variation, within the range of 10-90 phr, was studied with respect to the vulcanization process, static mechanical properties (tensile strength, elongation-at-break, hardness and resilience), dynamic mechanical properties and the morphology of the obtained vulcanizates. Butyl rubber was characterized by its low compatibility to other elastomers [i.e., natural rubber and styrene–butadiene rubber (SBR) -the main ingredients of tires] and low degree of unsaturation. To evaluate the impact of these factors on curing characteristics and mechanical properties of butyl rubber vulcanizates filled with GTR, the same compositions of SBR compounds, cured under identical conditions, were used as reference samples. Based on the obtained data, it can be stated that butyl rubber vulcanizates containing 30 phr of GTR as filler revealed the highest tensile strength and elongation-at-break. The microstructural analysis of a sample containing 30 phr of GTR revealed strong interactions between the butyl rubber matrix and GTR. This phenomenon resulted mainly from two factors. First, the cross-link density of the butyl rubber matrix was affected by its competition against GTR for cross-linking agents. Secondly, the migration of carbon black particles from GTR into the butyl rubber matrix had a significant impact on properties of the obtained vulcanizates.

Some of the desirable properties of concrete include high impact resistance and great energy-sucking capacity to name a few. These properties can be improved through the use of sustainable materials. This study investigated the effects of partly replacing fine aggregate with linear low-density polyethylene (LLDPE) and waste rubber (WR) as fine aggregates on the efficiency of concrete under impact loading. Two water to binder ratio (W/B) percentages of (0.40 and 0.55) were selected, with six (LLDPE-R) replacement grades (0%, 5%, 10%, 15%, 20%, and 30%) and two silica fume (SF) replacement grades (0% and 15%). Six cylinders with 150 and 60 mm were subjected to an impact by a 4.45 kg hammer striking. Test results indicated that impact resistance for the first visible crack and the ultimate failure increased with LLDPE-R content, where it increased by 4.76 times. This study also demonstrated that the impact resistance for the first visible crack of LLDPE-R concrete was improved by an average of 295% for specimens without SF and 292% for specimens containing SF. This enhancement for the ultimate failure is 291% and 290% for specimens without SF and containing SF, respectively.

Background and Objectives: Some of heavy metals such as copper (Cu) and manganese (Mn) are toxic and represent as hazardous pollutants due to their persistence in the environment. Heavy metals can be introduced into soils and aqueous environments by natural processes or anthropogenic activities. They are non-degradable in nature and highly toxic to plants, animals and human beings. Various methods exist for the removal of heavy metal ions from solution, such as filtration, chemical precipitation, ion exchange and sorption by activated carbon and others. Discarded tires are an interesting and inexpensive medium for the sorption of heavy metals. There has been little research on heavy metal sorption into tire rubber in competitive systems. Therefore the present study was conducted to assess the sorption behavior of Cu and Mn on different sizes of tire rubber in a competitive system.Materials and Methods: The finely ground discarded tire rubber with three sizes including 0.088-0.125, 0.177-0.250 and 0.353-0.500 mm were prepared from Yazd tire Company in Iran. A batch experiment was conducted by adding of 200 mg of ground tire to 10 ml of Cu+Mn aqueous solution of the desired concentration (10 to 50 mg L-1). After 24h, supernatant was separated by filtration and analyzed for remaining Cu and Mn by atomic absorption spectroscopy technique.Results: Sorption of Cu and Mn on tire rubber increased with increasing metal concentration from 0 to 50 mg L-1. The greatest sorption of Cu (1088.9 mg Kg-1) was found at the smallest tire rubber size (0.088-0.125 mm) and decreased by 35% when the largest size (0.353-0.500 mm) was used. At the highest concentration, sorption of Cu was restricted by Mn competition. In the whole range of studied metal concentrations, Mn occupied the least sorption sites of tire rubber. The sorption of Mn was not affected by tire rubber size and was restricted by Cu competition. Based on average, the experimental data were fitted in Langmuire (R2=0.94) better than Freundlich one (R2=0.87), showing monolayer sorption of Cu and Mn on discarded tire rubber. The values of maximum sorption capacities calculated from the fitted Langmuir equation showed that Cu sorption was higher than Mn. There was an increase in the qm values of Mn when the tire rubber diameter decreased. In this study, separation factor (RL) was used to predict if an adsorption system is favorable or unfavorable. In all cases, the values of RL were between 0 and 1, pointing to the favorable sorption of Cu and Mn on three size of rubber.Conclusion: Results clearly showed that ground discarded tire rubber (especially, the smallest size) are an effective adsorbent for the removal of Cu and Mn in competitive system. The equilibrium sorption isotherm of Cu and Mn onto discarded tire rubber is well described by the Langmuir and Freundlich models, but the Langmuir model fits the experimental data better than the Freundlich model.

There have recently been several initiatives to develop eco-sustainable materials because of the growing concern over ecological contamination caused by the overuse of synthetic materials. Previous studies in literature have explored the development of rice straw waste-based epoxy composites. Another waste hazard of concern in the current times is that of waste tire rubber. The present study investigates the physico-mechanical properties of a unique hybrid composite consisting of recycled waste tire rubber and rice straw reinforced composite, which has not been investigated in the literature. Their density, water absorption, hardness, tensile and flexural strengths were examined with variations in the proportion of rubber particles and rice husk. Increase in the rubber content resulted in proportional rise in the water uptake, hardness, tensile strength, and flexural strength. The composite with 25 wt.% of rubber and 5 wt.% of rubber showed the highest tensile strength and strain of 12.5 MPa and 0.015, respectively. The composite with 15% RS and WTR showed a 14.26% increase in flexural strength, with the neat composite exhibiting the highest strength. The composite material can be used as structural panels for instruments or devices in low load bearing applications. The developed sustainable material with waste generated from used tires and rice husk can aid in decreasing the harmful effects caused on the environment and human health during their disposal.

It is essential to keep the balance among rolling resistance, wet skid resistance and wear resistance (the so-called devil's triangle) of tire treads so as to ensure the reliability and safety of the vehicles. For this purpose, hexamethyl-disiloxane (HMDS) and carboxylated polyethylene vinyl acetate copolymer (EVA, emulsion polymer latex) were used to modify nanosilica by in situ surface-modification method, thereby obtaining surface-capped nanosilica possessing good compatibility and strong interfacial interactions with rubber matrix. The surface-capped nanosilica of the above both modifications were introduced into the blend of solution polymerized styrene butadiene rubber (SSBR) and butadiene rubber (BR), and its effect on the mechanical properties and wear resistance of the SSBR/BR-matrix nanocomposites was investigated. The results indicated that both HMDS and EVA contribute to enhancing the compatibility and interfacial interactions of nanosilica with the rubber matrix, which is favorable for improving the mechanical properties and wear resistance of SSBR/BR-matrix nanocomposites. Particularly, HMDS can endow the rubber-matrix nanocomposites with increased wet skid resistance, and EVA can ensure the low rolling resistance of the nanocomposites. Therefore, the SSBR/BR blend filled with HMDS–, SiO2–, EVA possesses the desired mechanical properties and wear resistance and shows promising prospective as a candidate material for fabricating high-performance tire tread.

Reusing recycled materials is one of the most important issues in the world for achieving sustainable development. Polyethylene Terephthalate, rubber, and glass particles are used instead of sand or cement in the concrete industry in recent years. In this paper, three groups of concrete mix designs with different water-to-cement ratios are investigated. Experimental specimens of each group consist of PET, rubber, and glass particles partially replacing natural fine aggregates by 5, 10, and 15 percent. These waste materials are used separately and in combination with each to study the mechanical properties of the concrete. Compressive and flexural strengths of concrete under different freezing and thawing cycles are investigated. The compressive strain of the recycled concrete was studied too. Results show that PET and rubber particles have decreasing effect on both compressive and flexural strengths of concrete and an increasing effect on compressive ultimate strains compared to those of reference specimens. But, the glass particles often have increasing and decreasing effects on strengths and strains respectively compared to those of reference specimens. The compressive strength of frozen-thawed recycled specimens is about 5 % more than that of the frozen-thawed reference specimen. Moreover, In combined PET and glass specimens, the experimental compressive and flexural strengths increased compared to only PET specimens and in combined PET-glass and PET-rubber specimens, the ultimate strain increased compared to that of glass concrete.