Rapid economic development and population growth, inadequate infrastructure and expertise, and land scarcity make the management of municipal solid waste become one of Malaysia's most critical environmental issues. The study is aimed at evaluating the generation, characteristics, and management of solid waste in Malaysia based on published information. In general, the per capita generation rate is about 0.5-0.8 kg/person/day in which domestic waste is the primary source. Currently, solid waste is managed by the Ministry of Housing and Local Government, with the participation of the private sector. A new institutional and legislation framework has been structured with the objectives to establish a holistic, integrated, and cost-effective solid waste management system, with an emphasis on environmental protection and public health. Therefore, the hierarchy of solid waste management has given the highest priority to source reduction through 3R, intermediate treatment and final disposal.
Biodegradable PLA is commonly derived from renewable resources and benign to the environment. It is a brittle thermoplastic with high strength and modulus; thus a suitable candidate for replacing conventional petroleum-based plastic. However, due to its limitation, PLA needs to be blended with other polymers and fillers for properties modifications. The aim of this work was to prepare PLA/PA6/GNP nanocomposites and characterize on the mechanical, thermal, chemical and dispersion of nanofiller in binary blend systems. PLA/PA6/GNP nanocomposites were blended by using a Haake twin screw extruder via melt intercalation method. The ratio of the polymer matrix was fixed at 20:80 and the processing temperature was in the range of 205 °C to 260 °C. Graphene nanoplatelet fillers were Plasticized polylactide/clay nanocomposites. I. The role of filler content and its surface organo-modification on the physico-chemical properties
Abstract:The recent air pollution trend, as well as the factors that contribute to the air quality, were reviewed in the Klang Valley since it has undergone rapid development over the years. The overall quality of air in the Klang Valley was moderate for 66% of the days throughout the year of 2009 while only 5% of the days were classified at the unhealthy level. Shah Alam and Kuala Lumpur were among the cities that recorded the highest number of unhealthy days from 2001-2009. Furthermore, places around the Klang Valley suffered from quite severe acidified rain, which indicates that heavy air pollution is still occurringin areas around the Lang Valley. Factors like urbanization, industry, motor vehicles and forest fires remain the main contributors to the deterioration of air quality in the Klang Valley. Hence, a more sustainable policy has to be introduced by the government in order to tackle the air pollution issue.
The discharge of industrial effluents, such as phenol, into aquatic and soil environments is a global problem due to its serious negative impacts on human health and aquatic ecosystems. In this study, the ability of polyvinylpolypyrrolidone (PVPP) to remove phenol from an aqueous medium was investigated. The results showed that a significant proportion of phenol (up to 74.91%) was removed using PVPP at pH 6.5. Isotherm adsorption experiments of phenol on PVPP indicated that the best-fit adsorption was obtained using Langmuir models. The response peaks of the hydroxyl groups of phenol (OH) and the carboxyl groups (i.e., CO) of PVPP were altered, indicating the formation of a hydrogen bond between the PVPP and phenol during phenol removal, as characterized using 1D and 2D IR spectroscopy. The resulting complexes were successfully characterized based on their thermodynamic properties, Mulliken charge, and electronic transition using the DFT approach. To clarify the types of interactions taking place in the complex systems, quantum theory of atoms in molecules (QTAIM) analysis, reduced density gradient noncovalent interaction (RDG-NCI) approach, and conductor-like screening model for real solvents (COSMO-RS) approach were also successfully calculated. The results showed that the interactions that occurred in the process of removing phenol by PVPP were through hydrogen bonding (based on RDG-NCI and COSMO-RS), which was identified as an intermediate type (∇2ρ(r) > 0 and H < 0, QTAIM). To gain a deeper understanding of how these interactions occurred, further characterization was performed based on adsorption mechanisms using molecular electrostatic potential, global reactivity, and local reactivity descriptors. The results showed that during hydrogen bond formation, PVPP acts as a nucleophile, whereas phenol acts as an electrophile and the O9 atom (i.e., donor electron) reacts with the H22 atom (i.e., acceptor electron).
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