Scandium is a rare earth element that has a wide range of uses in modern technology. The conventional recovery of scandium is commonly done by solvent extraction using organophosphorus compounds. This process however produces a lot of waste extractants. To circumvent this challenge, a model organophosphorus compound phenylphosphinic acid (PPI) was immobilized to a polymer support fabric to produce a Sc(III) adsorbent for high throughput scandium recovery with less waste generation. Polymer support (PP-g-PGMA)for the organophosphorus compound was synthesized using radiation-induced graft polymerization. Successful post-polymer modification of the PGMA grafts to attach PPI groups was carried out using 1 M PPI in isopropanol at 80 C for 4 h, achieving a maximum functional group density of 1.32 mmol/g. The obtained PP-g-PGMA-PPI fabrics were used in the batch Sc(III) adsorption experiments. The results showed that PP-g-PGMA-PPI effectively adsorbed low concentrations of Sc(III) at a pH of at least 2.0. More than 98% adsorption was achieved using 1 ppm Sc(III). The synthesized adsorbent was also shown to be selective for Sc(III) even in the presence of Fe(III) and Al(III) ions. PP-g-PGMA-PPI adsorbent fabrics are therefore promising alternatives to solvent extraction methods and ion-exchange granular resin technologies in the recovery of scandium.

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Super water absorbent (SWA) for agricultural applications must be optimized to withstand diminishing consequences in real soil system. A 33 × 12 full factorial design and soil water retention experiments were explored to optimize agricultural SWA made from acrylic acid (AA) and cassava starch. Four synthesis parameters such as degree of neutralization (DN), AA concentration, cassava starch concentration, and absorbed dose affecting the gel properties of SWA were investigated in the experimental design. The results showed that AA concentration and DN has strong interaction effects toward the degree of swelling (DS), gel fraction (GF), and gel strength (GS) of SWA. The soil water retention of SWA reduces with time due to microbial degradation and multivalent cations present in the soil. The optimum formulation is 20% AA 10% Starch 30% DN 10 kGy has predicted values (176 ± 68 g/g DS, 93 ± 5% GF, and 137 ± 23 kPa GS) close to the experimental values (132 ± 0.2 g/g DS, 91 ± 0.2% GF, and 141 ± 88 kPa GS). The chosen optimized formulation is 20% AA 7.5% starch 30% DN 20 kGy with 46% biodegradability after 218 days and stable soil water retention compared to commercial SWAs.

Chromium ions and other heavy metals discarded from major industries, if left unchecked, will make their way into waterways and may contaminate food crops, which can cause various chronic and acute health problems. As such, the Department of Science and Technology - Philippine Nuclear Research Institute (DOST-PNRI) developed radiation-grafted wastewater filters that selectively collect trivalent chromium ions from wastewater. To house these filters with the appropriate flow characteristics, column enclosures suitable for rapid prototyping via additive manufacturing, were designed and simulated. The column has two main components: the main chamber, which houses the filter; and an inner core, where the filter fabric is wound, and which evenly distributes the water flow along its length. Different core slit configurations were presented, giving emphasis on the flow uniformity, with the aim of maximizing the filter life.