Formation Of Tio2 Nanotubular Structure In Fluorinated Ethylene Glycol Electrolytes Containing Additives By Anodisation

TiO2 nanotube arrays (TNTs) have attracted significant interest as the most promising candidate for photo-induced reaction applications. The electrolyte composition is the one of critical factor for oxide formation by anodisation. The TNTs were fabricated in ethylene glycol (EG)/ ammonium fluoride (NH4F) electrolyte containing various additives (H2O, H2O2, KOH, LiOH and Na2CO3) as O2- and/or OH- providers. The properties including morphology, structural of formed oxide and crystallinity were investigated. The TNTs formed in EG/NH4F/H2O2 resulted in grassy structure (wall thickness ~ 10 nm) owing to high chemical etching at the tip of nanotubes. The TNTs formed in EG/NH4F/KOH electrolyte was partially crystalline with average tubes length 6.1 μm. The OH- ions suppress the excessive surface etching at the tips of nanotubes. Meanwhile, the addition of Na2CO3 in EG/NH4F electrolyte was successfully formed as-anodised free standing TNTs (FSTNTs) due to gas evolution which aids in weakening the adherence of anodic film on Ti. The as-anodised FSTNTs contain nanocrystallite anatase. The grassy TNTs demonstrated the highest photocatalytic decolouration efficiency of MO (91.7%) after 2 h owing to the capability of anatase phase to retain at 600 oC at the tip of grassy structure

Assessment of Electric Arc Furnace (EAF) Steel Slag Waste’s Recycling Options into Value Added Green Products: A Review

Steel slag is one of the most common waste products from the steelmaking industry. Conventional methods of slag disposal can cause negative impacts on humans and the environment. In this paper, the process of steel and steel slag production, physical and chemical properties, and potential options of slag recycling were reviewed. Since steel is mainly produced through an electric arc furnace (EAF) in Malaysia, most of the recycling options reviewed in this paper focused on EAF slag and the strengths and weaknesses of each recycle option were outlined. Based on the reports from previous studies, it was found that only a portion of EAF slag is recycled into more straightforward, but lower added value applications such as aggregates for the construction industry and filter/absorber for wastewater treatments. On the other hand, higher added value recycling options for EAF slag that are more complicated such as incorporated as raw material for Portland cement and ceramic building materials remain at the laboratory testing stage. The main hurdle preventing EAF slag from being incorporated as a raw material for higher added value industrial applications is its inconsistent chemical composition. The chemical composition of EAF slag can vary based on the scrap metal used for steel production. For this, mineral separation techniques can be introduced to classify the EAF slag base on its physical and chemical compositions. We concluded that future research on recycling EAF slag should focus on separation techniques that diversify the recycling options for EAF slag, thereby increasing the waste product’s recycling rate