[Measurement of dissolved organic nitrogen with nanofiltration pretreatment and its distribution characteristics in landscape water].
In this study, we present a nanofiltration (NF90, NF270) pretreatment to increase the precision of dissolved organic nitrogen (DON) measurements in water samples. The variations of DON measurements with and without NF pretreatment were investigated. And the effects on the removal of dissolved inorganic nitrogen (DIN) by NF90 and NF270 were compared. As shown in the results, the average removal rates reached 30.7%, 55.9% of NH4(+)-N, 50.0%, 73.1% of NO3(-) -N and 42.9%, 72.0% of NO2(-)-N for NF90 and NF270 pretreatment, respectively. NF270 was obviously more effective to remove the DIN species. Concentrations of DON measured using traditional methods varied from 0.09 to 0.46 mg x L(-1), with negative concentration (-0.08 mg x L(-1)) at site 2 and the DIN/TDN ratio ranged from 85.3% to 105%; while the concentrations of DON measurements varied from 0.03 to 0.58 mg x L(-1), and the DIN/TDN ratio ranged from 76.1% to 90.6% for NF90 pretreatment and varied from 0.10 to 0.59 mg x L(-1), and the DIN/TDN ratio ranged from 47.5% to 84.5% for NF270 pretreatment. The results indicated that nanofiltration pretreatment could effectively remove the DIN species, decrease the standard deviation of DON measurements and increase the precision of DON measurements. The distribution of DON in water samples of Beijing Olympic Forest Park was investigated. The results showed that there was seasonal variation in the concentrations of DON in landscape water from the Olympic Forest Park. And there was significant difference between the north and south part. The DON concentrations were less than 0.2 mg x L(-1) in November, March and May and higher in July in the north part, while the DON concentrations were lower in May and higher in November and March in the south part, ranging from 0.40-0.65 mg x L(-1).
College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, China. techie1010@163.com
Hong-Lei
HL
Yu
Shou-Liang
SL
Huo
Zhou-Sheng
ZS
Yang
Bei-Dou
BD
Xi
Feng-Yu
FY
Zan
Jing-Tian
JT
Zhang
D005374:Filtration / Q000379:methods; D005618:Fresh Water / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D009584:Nitrogen / Q000032:analysis*; D009930:Organic Chemicals / Q000032:analysis*; D012621:Seasons; D012995:Solubility
D009930:Organic Chemicals; D009584:Nitrogen