The sago starch industry is one of the major revenue sources of the Malaysian state of Sarawak. This state is currently among the world’s leading producers of sago starch, exporting more than 40,000 tons every year to different Asian countries. This number is expected to rise since starch production and export value have been increasing 15.0%– 20.0% each year. Sago palm is subjected to various processes to obtain starch from its trunk. During processing, a huge amount of residual solid wastes is generated, such as bark and hampas, and in general, is burned or washed off to nearby streams. Along with the rising sago starch demand, the sago starch industry is now facing waste management problems, which have resulted in environmental pollution and health hazards. These wastes comprise starch, hemicellulose, cellulose, and lignin; hence, can be valorized into feedstock as value-added products. To date, these wastes have been utilized in the production of many materials like adsorbents, sugars, biofuels, nanomaterials, composites, and ceramics. This review article aims to summarize the various methods by which these wastes can be utilized besides to enlighten the major interest on sago hampas and bark.
Tin selenide (SnSe) and copper indium diselenide (CuInSe2) compounds were synthesized by high temperature reaction method using combination of sealed ampoule (at relatively low pressure ~10-1 Pa without inert gas) and heating at specific temperature profile in rocking furnace. Powder X-Ray diffraction analysis showed that the products involved only single phases of SnSe and of CuInSe2 only. Using the reaction products as source materials, the SnSe and CuInSe2 thin films were vacuum-deposited on glass substrates at room temperature. Structural, elemental, surface morphological and optical properties of the as-deposited films were studied by X-Ray diffraction (XRD), energy dispersive X-Ray (EDX) analysis, field emission scanning electron microscopy (FESEM) and UV-Vis-NIR spectroscopy. Single phase of SnSe and CuInSe2 films were obtained by thermal evaporation technique from synthesized SnSe and CuInSe2 compound without further treatment.