Preparation of Poly (Allylthiourea-Co-Acrylic Acid) Derived Carbon Materials and Their Applications in Wastewater Treatment.

Functional carbon materials have been developed and applied in various sewage treatment applications in recent years. This article reports the fabrication, characterization, and application of a new kind of poly (allylthiourea-co-acrylic acid) (PAT⁻PAC) hydrogel-based carbon monolith. The results indicated that the poly acrylic acid component can endow the PAT⁻PAC hydrogel with an increased swelling ratio and enhanced thermal stability. During the carbonization process, O⁻H, N⁻H, C=N, and ⁻COO⁻ groups, etc. were found to be partly decomposed, leading to the conjugated C=C double bonds produced and the clear red shift of C=O bonds. Particularly, it was found that this shift was accelerated under higher carbonization temperature, which ultimately resulted in the complex conjugated C=C network with oxygen, nitrogen, and sulfur atoms doped in-situ. The as-obtained carbon monoliths showed good removal capacity for Ni(II) ions, organic solvents, and dyes, respectively. Further analysis indicated that the Ni(II) ion adsorption process could be well described by pseudo-second-order and Freundlich models under our experimental conditions, respectively. The adsorption capacity for Ni(II) ions and paraffin oil was as high as 557 mg/g and 1.75 g/g, respectively. More importantly, the as-obtained carbon monoliths can be recycled and reused for Ni(II) ions, acetone, and paraffin oil removal. In conclusion, the proposed PAT⁻PAC-based carbonaceous monoliths are superior adsorbents for wastewater treatment.

Use of luminescence probing for the study of the interaction of polytitanasiloxane with trivalent rare earth ions.

Luminescent probing methods were employed to investigate the interaction of the Ti-O chains of polytitanasiloxane with europium ions in the mixture of ethanol and water. The UV-vis absorption, the luminescence intensity, and the luminescence lifetimes of the Eu3+ ions in PTS solutions were all found to increase with the increase of TBT/TEOS molar ratio. The results indicated that the incorporation of TBT can result in the increase of absorption energy of the Ti-O group by near-UV excitation and in the increase of energy transfer to the metal ion, and that the Ti-O chains due to the site binding of Eu3+ ions can expel six to nine solvent molecules from the first coordination solvation shell of the ion. The investigation of the energy transfer from europium to neodymium ions in polytitanasiloxane solutions revealed the formation of aggregates consisting of seven rare earth ions (together with the polytitanasiloxane countercharges).

Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH)2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH)2-glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl2) at room temperature, but that in Ca(OH)2-water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH)2 pretreatment.