A series of choline carboxylate ionic liquids (ILs) have been synthesized by neutralization of choline hydroxide solution with acetic, propanoic, butanoic, pivalic, and hexanoic acids. The salts so obtained were characterized by NMR spectroscopy, thermal methods, and elemental analysis. Key physical properties (density, viscosity, and refractive index) were measured for the propanoate, butanoate, and hexanoate salts at temperatures from (293.15 to 353.15) K. The densities were used to estimate the molecular volumes, standard entropies, crystal lattice energies, and thermal expansion coefficients. All five choline carboxylates were found to have cytotoxicities (IC 50 values) above 10 mM toward the human breast cancer cell line, MCF-7, indicating they are much less toxic than common imidazolium-based ILs.

The characteristics and water/oil sorption effectiveness ofkapok fibre, sugarcane bagasse and rice husks have been compared. The three biomass types were subjected to field emission scanning electron microscopy-energy dispersive X-ray spectroscopy and surface tension analyses for liquid-air and oil-water systems were conducted. Both kapok fibre and sugarcane bagasse exhibit excellent oil sorption capabilities for diesel, crude, new engine and used engine oils as their oil sorption capacities all exceed 10 g/g. The synthetic sorbent exhibits oil sorption capacities comparable with sugarcane bagasse, while rice husks exhibit the lowest oil sorption capacities among all the sorbents. Kapok fibre shows overwhelmingly high oil-to-water sorption (O/W) ratios ranging from 19.35 to 201.53 while sugarcane bagasse, rice husks and synthetic sorbent have significantly lower O/W ratios (0.76-2.69). This suggests that kapok fibre is a highly effective oil sorbent even in well-mixed oil-water media. An oil sorbent suitability matrix is proposed to aid stakeholders in evaluating customized oil removal usage of the natural sorbents.

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Malaysia is gradually experiencing scarcity of available land for development. As such, the local government is currently looking into the possibility of employing high-end and largescale incineration processes to address this issue. MSW as a combustion source for thermochemical conversion application, represents a two-pronged approach in solving its disposal dilemma as well as providing a source of energy fuel. This paper highlights the current issues and future directions as well as energy recovery initiatives associated with incineration of MSW in Malaysia. In Malaysia, energy recovery initiatives are focused on application of waste-to-energy (WTE) as well as refuse-derived fuel (RDF) technologies.Aspects regarding MSW landfill gas capture and energy generation are also discussed since they may directly influence (or potentially compete against) the widespread adoption of RDF technologies. A relatively successful RDF pilot plant in Malaysia is highlighted as a case study. It is deemed that application of large-scale incineration technologies in Malaysia is inevitable as opening of new landfill areas will ultimately cease in the future.