Utilization of Oxygen Models in Environmental Impact Analysis

1977 ◽  
Vol 12 (1) ◽  
pp. 135-156 ◽  
Author(s):  
W.J. Snodgrass ◽  
M.F. Holloran

Abstract A vertical one-dimensional temperature-oxygen model for reservoirs is used to estimate zones of stress on the aquatic environment of a series of reservoirs in Nova Scotia. Application to cold climates necessitated a few novel developments for the temperature model. The oxygen model whose sinks are water column decay and sediment oxygen demand (SOD) is calibrated using under ice measurements of oxygen stocks and laboratory and in situ measurements of a zero-order kinetic model for sediment oxygen demand. These extensive studies are complementary and indicate a winter SOD of 0.1 gm 02/m2/day and a higher summer value. High epilimnetic temperatures coupled with the predicted anoxic zones in lower waters cause a major stress upon fisheries potential. This model provides a tool for determining the effects of different reservoir management strategies upon water quality and for selecting among these strategies.

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 454 ◽  
Author(s):  
Aili Wang ◽  
Shuhui Li ◽  
Hou Chen ◽  
Ying Liu ◽  
Xiong Peng

This paper reports the successful construction of novel polymerizable ionic liquid microemulsions and the in situ synthesis of poly(ionic liquid) adsorbents for the removal of Zn2+ from aqueous solution. Dynamic light-scattering data were used to confirm the polymerization media and to illustrate the effect of the crosslinker dosage on the droplet size of the microemulsion. FTIR and thermal analysis were employed to confirm the successful preparation of the designed polymers and characterize their thermostability and glass transition-temperature value. The optimization of the adsorption process indicates that the initial concentration of Zn2+, pH, adsorbent dosage and contact time affected the adsorption performance of poly(ionic liquid)s toward Zn2+. Furthermore, our research revealed that the adsorption process can be effectively described by the pseudo second-order kinetic model and the Freundlich isotherm model.


2015 ◽  
Vol 73 (5) ◽  
pp. 1155-1165 ◽  
Author(s):  
J. D. García-Espinoza ◽  
P. Gortáres-Moroyoqui ◽  
M. T. Orta-Ledesma ◽  
P. Drogui ◽  
P. Mijaylova-Nacheva

Carbamazepine (CBZ) is one of the most frequently detected organic compounds in the aquatic environment. Due to its bio-persistence and toxicity for humans and the environment its removal has become an important issue. The performance of the electrochemical oxidation process and in situ production of reactive oxygen species (ROS), such as O3 and H2O2, for CBZ removal have been studied using Ti/PbO2 cylindrical mesh anode in the presence of Na2SO4 as supporting electrolyte in a batch electrochemical reactor. In this integrated process, direct oxidation at anode and indirect oxidation by in situ electrogenerated ROS can occur simultaneously. The effect of several factors such as electrolysis time, current intensity, initial pH and oxygen flux was investigated by means of an experimental design methodology, using a 24 factorial matrix. CBZ removal of 83.93% was obtained and the most influential parameters turned out to be electrolysis time, current intensity and oxygen flux. Later, the optimal experimental values for CBZ degradation were obtained by means of a central composite design. The best operating conditions, analyzed by Design Expert® software, are the following: 110 min of electrolysis at 3.0 A, pH = 7.05 and 2.8 L O2/min. Under these optimal conditions, the model prediction (82.44%) fits very well with the experimental response (83.90 ± 0.8%). Furthermore, chemical oxygen demand decrease was quantified. Our results illustrated significant removal efficiency for the CBZ in optimized condition with second order kinetic reaction.


1983 ◽  
Vol 17 (6) ◽  
pp. 603-605 ◽  
Author(s):  
Bruce E. Markert ◽  
Michael G. Tesmer ◽  
Peter E. Parker

2021 ◽  
Vol 37 (4) ◽  
pp. 922-927
Author(s):  
A. Kistan ◽  
V. Kanchana ◽  
N. K. Geetha ◽  
G. Infant Sujitha

The following study explains that the adsorption efficiency of activated carbon used by Groundnut foliage and groundnut husk for the deportation of COD (Chemical Oxygen demand) from groundwater collected from in and around industrial areas of Vellore district was investigated with different activating conditions (Activating agent- KOH, ZnCl2 and H3PO4; Impregnation ratio-1:1,1:2,1:2; and activation temeperture-500-700°C. The activated carbon prepared based on optimized condition has well-developed pore structure and functional groups which is confirmed from SEM image and FTIR analysis respectively. The adsorption equilibrium was reached in 240 min with the isotherm data fitted well in both the model such as Langmuir model and Freundlich’s model indicating chemisorption’s adsorption for the activated carbon. Moreover, the adsorption process was exothermic accompanied by a decrease in irregularity. Furthermore, the adsorption kinetic study indicated that the adsorption process of the prepared sample follows the pseudo-second-order kinetic model compare to the pseudo-first -order kinetic model


2019 ◽  
Vol 48 (2) ◽  
pp. 403-411
Author(s):  
Erin N. Coenen ◽  
Victoria G. Christensen ◽  
Lynn A. Bartsch ◽  
Rebecca M. Kreiling ◽  
William B. Richardson

2013 ◽  
Vol 750-752 ◽  
pp. 47-50
Author(s):  
Wen Juan He ◽  
Yu Feng He ◽  
Zhen Hua Zhang ◽  
Ju Hua Guo ◽  
Rong Min Wang

In this paper, a new kind of clay copolymer adsorbent, bentonite compositing with maleic anhydride (MAH)-acrylic acid (AA)-vinyl acetate (VAc) copolymer (NaB/PMAV) was prepared by in-situ polymerization. It was used as polymer adsorbent for removing Pb (II) ions in wastewater.. Under the optimal condition of adsorption, the removal rate reached to 94.4% and the adsorption capacity got to 235.9 mg/g. Adsorption dynamics were consistent with pseudo-second-order kinetic model and isotherm model can meet the Langmuir isotherm.


2018 ◽  
Vol 77 (10) ◽  
pp. 2377-2387 ◽  
Author(s):  
P. M. D'Aoust ◽  
F. R. Pick ◽  
R. Wang ◽  
A. Poulain ◽  
C. Rennie ◽  
...  

Abstract Stormwater retention ponds can play a critical role in mitigating the detrimental effects of urbanization on receiving waters that result from increases in polluted runoff. However, the benthic oxygen demand of stormwater facilities may cause significant hypoxia and trigger the production of hydrogen sulfide (H2S). This process is not well-documented and further research is needed to characterize benthic processes in stormwater retention ponds in order to improve their design and operation. In this study, sediment oxygen demand (SOD), sediment ammonia release (SAR) and sediment sulfide production (SSP) kinetics were characterized in situ and in the laboratory. In situ SOD and SSP data were utilized to develop a stormwater retention pond water sulfide concentration model which demonstrates strong correlation with sulfide concentrations observed in situ (r = 0.724, N = 91, p < 0.001) and in laboratory experiments (r = 0.691, N = 38, p < 0.001). At 4 °C, in situ rates of SOD, SAR and SSP were higher than those measured in laboratory. Sulfate-reducing bacteria (SRB) represented 4.99% of the bacteria present in the top 30 cm of the pond sediment, with Desulfobulbaceae spp., Desulfobacteraceae spp. and Desulfococcus spp. being the dominant SRB taxa identified.


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