Universiti Teknologi Petronas

About: Universiti Teknologi Petronas is a education organization based out in Ipoh, Malaysia. It is known for research contribution in the topics: Adsorption & Ionic liquid. The organization has 6127 authors who have published 11284 publications receiving 119400 citations.

Utilization of recycled tiles and tyres in stabilization of soils and production of construction materials – a state-of-the-art review

Abstract: Tile waste is found in several forms including manufacturing slurry, manufacturing dust, and solid pieces from cracked, smashed, and rejected tiles at the construction sites. Worn out tyres that are no longer safe to be used by vehicles are either discarded or burned, adversely impacting natural ecosystems. These wastes are non-degradable and have a direct environmental impact. Poor waste management can lead to hazardous pollution, reduced soil fertility, and increased space consumption at disposal sites. The massive and increasing volume of the tile and tyre wastes calls for recycling of the materials for economical reuse, cleaner production, and greener development. One area for beneficial reuse of these waste materials is the improvement of engineering properties in soft soil. Structures on soft soils may experience several forms of damage due to insufficient bearing capacity and excessive settlement. Hence, soil stabilization is often necessary to ensure that the soft soil can meet the engineering requirements for stability. A comprehensive review of the published literature on the use of recycled tyres and tiles to stabilize and enhance soft soils was carried out. The properties of soft soil-waste mixtures such as liquid limit, plastic limit, plasticity index, compaction behaviour, unconfined compressive strength, and California Bearing Ratio have been presented. When used as partial replacement of cement, sand, and aggregate in concrete, the effect of tyre and tile waste on workability, durability, and compressive strength of the concrete has also been presented. Recycled tiles and tyres have been used with or without any other admixtures to sustainably improve the strength and bearing capacity of soil. The suitability of recycled tiles and tyres in soil stabilization has been discussed with regard to enhancement of strength and reduction of settlement. In addition, the beneficial effects of the recycled tiles and tyres, when they partially replace cement, sand or stone in concrete, have been discussed.

Charge Transfer Evidence between Carbon Nanotubes and Encapsulated Conjugated Oligomers

Abstract: A hybrid system consisting of quaterthiophene derivative inserted into carbon nanotubes is studied. Encapsulation efficiency of the conjugated oligomers in the hollow core of nanotubes is investigated by transmission electron microscopy and spatial-resolved electron energy loss spectroscopy. Infrared spectroscopy showed evidence of a significant positive charge transfer on the inserted oligothiophene. Raman spectra display different behaviors depending on the excitation energy and correlated to the quaterthiophene optical absorption energy. At high excitation wavelength (far from the oligomer resonance), radial breathing modes exhibit a significant upshift consistent with an encapsulation effect. At low excitation wavelength (close to the oligomer resonance), both the G-band shift and the low-frequency modes vanishing suggest a significant charge transfer between the quaterthiophene and the nanotubes.

Adsorption of chrysene in aqueous solution onto MIL-88(Fe) and NH2-MIL-88(Fe) metal-organic frameworks: kinetics, isotherms, thermodynamics and docking simulation studies

Abstract: MIL-88(Fe) and NH2-MIL-88(Fe) metal-organic frameworks were synthesized using the microwave-assisted solvothermal method and were characterized using scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), powdered X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. Relatively high surface areas with corresponding pore volumes of 1240 m2 g−1 and 0.7 m3 g−1, 941 m2 g−1 and 0.6 m3 g−1 were found for MIL-88(Fe) and NH2-MIL-88(Fe), respectively. The MOFs were evaluated as adsorbent for the removal of chrysene (CRY) in water. Important parameters that affect the adsorption such as contact time, initial concentration of CRY, pH and temperature were systematically studied. Adsorption isotherms using Langmuir, Freundlich and Temkin models were investigated. Other details of the adsorption process were also studied using kinetics and thermodynamics approaches. Additionally, molecular docking was used to unravel the nature of the adsorption between the MOFs and CRY. The reusability of the adsorbents was evaluated using regeneration studies. In conclusion, these MOFs exhibit favorable characteristics to be used for the removal of CRY from water.