Recovery of carbon fiber from carbon fiber reinforced plastics using alkali molten hydroxide.

High-strength carbon fibers were recovered by a new method, involving the decomposition of the thermosetting resin part of carbon fiber-reinforced plastic (CFRP) by heating it in a mixture of sodium hydroxide (NaOH) and potassium hydroxide (KOH). Alkali molten hydroxide was prepared by heating the mixture of NaOH and KOH at various ratios (NaOH: KOH = 1:0, 3:1, 1:1, 1:3, 0:1) at 400C, and the CFRP was then heated with the aforementioned alkali molten hydroxide under a nitrogen atmosphere at 200-400C for 0-90 min. Subsequently, the CFRP was washed with distilled water and filtered to recover the carbon fibers, and its tensile strength was estimated.

Ion exchange properties of Japanese natural zeolites in seawater.

Ion exchange properties of five different Japanese natural zeolites in seawater were examined. Sodium ions could be reduced by all zeolites, although anions, Cl(-) and SO(4)(2-), in seawater showed barely changes. Natural zeolite desalination treatment mainly depends on the ion exchange between Na(+), K(+) and Mg(2+) in seawater and Ca(2+) in natural zeolite.

Material conversion from paper sludge ash in NaOH solution to synthesize adsorbent for removal of Pb2+, NH4+ and PO4(3-) from aqueous solution.

Material conversion from paper sludge ash (PSA) in NaOH solution was attempted to synthesize the adsorbent for removal of inorganic pollutants, such as Pb2+, NH4+ and PO4(3-) from aqueous solution. PSA of 0.5 g was added into 10 mL of 3 mol/L NaOH solution, and then heated at 80, 120, and 160 degrees C for 6-48 hr to obtain the product.

Heavy metal removal from aqueous solution using carbonaceous K2S-impregnated adsorbent.

A novel carbonaceous adsorbent for heavy metal removal was prepared from raw coal by one-step simple sulfur impregnation using K2S. Raw coal was mixed with K2S powder and then heated at 800 degrees C for 30 min in nitrogen to produce K2S char. The sulfur content and form in K2S char were determined, and the ability of K2S char to adsorb Zn2+, Cd2+ and Pb2+ was examined.

Synthesis of zeolites from paper sludge ash and their ability to simultaneously remove NH4+ and PO43-.

The objective of this study was to investigate the synthesis of zeolites from paper sludge ash, and to evaluate their applications for water purification to simultaneously remove NH4+ and PO43- in aqueous solution. Paper sludge ash had a low abundance of Si and a significant Ca content, due to the presence of calcite that was used as paper filler. Na2SiO3 was added to the NaOH solution to increase Si content in order to synthesize zeolites with high cation exchange capacity.

Zeolite synthesis from paper sludge ash at low temperature (90 degrees C) with addition of diatomite.

Paper sludge ash was partially converted into zeolites by reaction with 3M NaOH solution at 90 degrees C for 24 h. The paper sludge ash had a low abundance of Si and significant Ca content, due to the presence of calcite that was used as a paper filler. Diatomite was added to the NaOH solution to increase its Si content in order to synthesize zeolites with high cation exchange capacity.