ABSTRACT
In this study, conversion of sewage sludge to biogas by anaerobic co-digestion with crude glycerol was examined. When 0.126g/L crude glycerol was added to the reactor, only methane was produced. Upon addition of 5.04g/L crude glycerol, hydrogen production occurred, and a significant amount of 1,3-propanediol (1,3-PDO) was generated in the liquid phase. On day 6, the dry weight was largely composed of organic acids (48%) and 1,3-PDO (17%), which are water-soluble. Degradation of 1,3-PDO was very slow, which is advantageous for recovery. Crude glycerol, which contains alkaline substances, promoted organic matter degradation by microorganisms, which possibly affected biogas and 1,3-PDO production. Addition of 0.630-2.52g/L glycerol initially led to hydrogen production, followed by methane production a few days later, which stabilized within 1week. In conclusion, adjustment of the crude glycerol concentration allows controllable conversion to value-added products for co-digestion.
Subject(s)
Glycerol/metabolism , Sewage/chemistry , Anaerobiosis , Biofuels , Biomass , Bioreactors , Fermentation , Hydrogen/metabolism , Methane/biosynthesis , Propylene Glycols/metabolism , SolubilityABSTRACT
Liquid-liquid extraction of lanthanides from aqueous solutions into ionic liquids (ILs) has been investigated using N,N,N',N'-tetra(n-octyl)diglycolamide (TODGA) as an extractant, and compared with that in the isooctane system. Application of ILs as the extracting phase provided unprecedented enhancement of the extraction performance of TODGA for lanthanides compared with that of the isooctane system. Slope analysis confirmed that TODGA in ILs formed a 1:3 complex with La3+, Eu3+, or Lu3+. On the other hand, the molar ratios of species extracted into isooctane were 1:3 for La3+ or 1:4 for Eu3+ and Lu3+, depending on the atomic number of the lanthanide. The transfer of lanthanides with TODGA into ILs proceeded via a cation-exchange mechanism, in contrast to ion pair extraction in the isooctane system. Furthermore, we clarified that TODGA provided selectivity for the middle lanthanides in the ILs systems, but heavier lanthanides in the isooctane system.
Subject(s)
Glycolates/chemistry , Ionic Liquids/chemistry , Lanthanoid Series Elements/chemistry , Organometallic Compounds/chemical synthesis , Molecular Structure , Nitric Acid/chemistry , Organometallic Compounds/chemistry , Reproducibility of Results , Solubility , Sulfuric Acids/chemistryABSTRACT
Novel 4-acyl-5-pyrazolones having aza-15-crown-5 (HPMP-A15C5) and aza-18-crown-6 (HPMP-A18C6) moieties as an intramolecular synergist have been synthesized by simple coupling reactions between 1-phenyl-3-methyl-4-chloroacetyl-5-pyrazolone and the corresponding azacrown ethers. The solvent extraction of the divalent metal ions (Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+) and Pb(2+)) were examined. Synergistic extractions with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP) and benzocrown ethers were also examined for a comparison. Extractions with the novel acylpyrazolones were unique and quite different from those with HPMBP and benzocrown ethers. The synergistic effect with benzocrown ethers was low, and an obvious difference brought by the ring size was not observed. The extractions of the divalent metal ions with HPMP-A18C6 were generally enhanced, as compared to those alone with HPMBP; on the contrary, the extractions with HPMP-A15C5 were relatively poor.