Ammonia nitrogen removal and recovery from acetylene purification wastewater by air stripping.

Ammonia nitrogen (NH-N) contaminated wastewater has posed a great threat to the safety of water resources. In this study, air stripping was employed to remove and recover NH-N from acetylene purification wastewater (APW) in a polyvinylchloride manufacturing plant. Investigated parameters were initial APW pH, air flow rate, APW temperature and stripping time.

Ammonia nitrogen removal from acetylene purification wastewater from a PVC plant by struvite precipitation.

Acetylene purification wastewater (APW) usually contains high concentrations of ammonia nitrogen (NH4-N), which is generated during the production of acetylene in a polyvinylchloride manufacturing plant. In this study, a struvite precipitation method was selected to remove NH4-N from the APW. Laboratory-scale batch experiments were performed to investigate the effects of the initial APW pH, phosphate (PO4(3-)) concentration, magnesium (Mg(2+)) concentration, and sources of PO4(3-) and Mg(2+) on NH4-N removal.

{N'-[(2-Oxidonaphthalen-1-yl)methyl-idene]benzohydrazidato}(1,10-phenanthroline)copper(II) methanol monosolvate.

The title mononuclear complex, [Cu(C(18)H(12)N(2)O(2))(C(12)H(8)N(2))]·CH(3)OH, contains one N'-[(2-oxidonaphthalen-1-yl)methyl-idene]benzohydrazidate ligand (L(2-)), a Cu(2+) cation, one 1,10-phenanthroline ligand and a methanol solvent mol-ecule. The Cu(II) ion adopts a CuO(2)N(3) distorted square-pyramidal coordination. An O-H⋯O hydrogen bond is formed between the methanol solvent mol-ecule and the hydrazide O atom of the L(2-) ligand.

Kinetics and thermodynamics of sorption of nitroaromatic compounds to as-grown and oxidized multiwalled carbon nanotubes.

The sorption kinetics and thermodynamics of 1,3-dinitrobenzene (DNB), m-nitrotoluene (mNT), p-nitrophenol (pNP), and nitrobenzene (NB) on as-grown and nitric acid-oxidized multiwalled carbon nanotubes (MWCNTs) were investigated. The sorption kinetics was well described by a pseudo-second-order rate model, while both Langmuir and Freundlich models described the sorption isotherms well and the sorption thermodynamic parameters of equilibrium constant (K(0)), standard free energy (DeltaG), standard enthalpy (DeltaH), and standard entropy changes (DeltaS) were measured. The values of DeltaH and DeltaG suggested that the sorption of nitroaromatics (NACs) onto MWCNTs was exothermic and spontaneous.

Adsorption of Pb, Cd to Fe, Mn oxides in natural freshwater surface coatings developed in different seasons.

Metal oxides( Fe, Mn oxides) in natural surface coatings(biofilms and associated minerals) are believed to play a significant role in the fate and transport of trace metal in aquatic environments. Seasonal variation of Fe, Mn oxides and organic materials in surface coatings, which were developed periodically on glass slides in Nanhu Lake, Jilin Province, China over the time frame of three seasons, was investigated in order to understand the influence of metal oxides on Pb and Cd adsorption to heterogeneous surface coating materials (biofilm). Pb and Cd adsorption was measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0.

Lead adsorption capacities of different components in natural surface coatings.

Pb adsorption capacities of Fe oxide, Mn oxide and organic materials in natural surface coatings( biofilms and associated minerals) collected in three lakes, two ponds and a river in Jilin Province, China and Cayuga Lake in US were studied. A novel extraction technique was employed to remove one or more component(s) from the surface coatings. Pb adsorption to surface coatings before and after extraction was performed to determine the adsorptive properties of the extracted component(s).