scholarly journals Membrane Distillation: Pre-Treatment Effects on Fouling Dynamics

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 958
Author(s):  
Paula G. Santos ◽  
Cíntia M. Scherer ◽  
Adriano G. Fisch ◽  
Marco Antônio S. Rodrigues
Keyword(s):  
Mathematical Model ◽  
Coupling Agent ◽  
Treatment Effects ◽  
Membrane Distillation ◽  
Bulk Flow ◽  
Ph Adjustment ◽  
Fouling Mechanism ◽  
Pre Treatment ◽  
Deposit Layer

In the research reported in this paper, membrane distillation was employed to recover water from a concentrated saline petrochemical effluent. According to the results, the use of membrane distillation is technically feasible when pre-treatments are employed to mitigate fouling. A mathematical model was used to evaluate the fouling mechanism, showing that the deposition of particulate and precipitated material occurred in all tests; however, the fouling dynamic depends on the pre-treatment employed (filtration, or filtration associated with a pH adjustment). The deposit layer formed by particles is not cohesive, allowing its entrainment to the bulk flow. The precipitate fouling showed a minimal tendency to entrainment. Also, precipitate fouling served as a coupling agent among adjacent particles, increasing the fouling layer cohesion.

scholarly journals ENVIRONMENTAL AND SEED TREATMENT EFFECTS ON GERMINATION AND GROWTH OF INDIAN PAINTBRUSH

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1100b-1100
Author(s):  
Pamela Borden
Keyword(s):  
Growth Regulator ◽  
Seed Treatment ◽  
Host Plants ◽  
Treatment Effects ◽  
Additional Data ◽  
Early Growth ◽  
Distilled Water ◽  
Native Grasses ◽  
Pre Treatment ◽  
Germination And Growth

Indian Paintbrush (genus Castilleja) is a group of attractive wildflowers in which some species are facultative parasites on native grasses during early growth. This study hopes to characterize optimum germination, cultural and host requirements of several species. Lots of 100 seed of wild-collected Castilleja coccinea (L.) Spreng. produced 22% germination without pre-treatment or presence of host plants 10 days after seeding at 21°C with 12 hours light. Seed soaked 24 hours in distilled water, 10 mg/l GA3 or-post-plant treated with Regal Crown nutrient and growth regulator soluotion did not significantly differ from above. Moist stratification at 4°C for 20 days significantly increased germination to 46%. Further stratification (up to 80 days) did not further increase germination. Additional data on light, temperature, media and presence of host plants will also be presented for this and other species.

scholarly journals Desalination of Produced Water by Membrane Distillation: Effect of the Feed Components and of a Pre-treatment by Fenton Oxidation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Francesco Ricceri ◽  
Mattia Giagnorio ◽  
Giulio Farinelli ◽  
Giulia Blandini ◽  
Marco Minella ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Produced Water ◽  
Membrane Distillation ◽  
Fenton Oxidation ◽  
Produced Waters ◽  
Pre Treatment ◽  
High Concentrations ◽  
Membrane Wetting ◽  
By Products

Abstract The treatment of produced waters (by-products of oil and gas extraction) with the innovative process of membrane distillation is challenging, because these highly saline streams contain high concentrations of organic compounds and hydrocarbons that cause membrane wetting and impairment of performance. To design the most compact treatment scheme and with the aim of obtaining an easier management of produced water for reuse purposes, Fenton oxidation is here investigated as a feed pre-treatment that may produce an effluent easily handled by membrane distillation. In high-recovery membrane distillation tests, we systematically investigate the detrimental effects of individual contaminants in a synthetic produced water mimicking the composition of a real sample. The recovery rate depends strongly on the initial salinity, which eventually causes scaling and pore blocking. Surfactants are found to be mainly responsible for membrane wetting, but volatile and hydrophobic organics also spoil the quality of the product water. A Fenton oxidation pre-treatment is thus performed to degrade the target organics, with the aim of enhancing the effectiveness of the following membrane distillation and to improve the quality of the final product. The combined oxidation-membrane distillation scheme has both advantages and limitations, which need to be carefully evaluated and further investigated.

Cervix cancer regression measured using weekly MR imaging during fractionated radiotherapy: Radiobiologic modeling and correlation with tumor hypoxia

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 5547-5547
Author(s):  
K. S. Lim ◽  
P. Chan ◽  
R. Dinniwell ◽  
A. Fyles ◽  
M. Haider ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Regression Analysis ◽  
Linear Regression ◽  
Mr Imaging ◽  
Tumor Volume ◽  
Tumor Regression ◽  
Linear Regression Analysis ◽  
Tumor Hypoxia ◽  
Cervix Cancer ◽  
Pre Treatment

5547 Background: To utilize cervix cancer volumetry, as measured with MR imaging during definitive chemoirradiation (RT-CT), to derive radiobiological parameters using a mathematical model of tumor regression, and compare them to pre-treatment measurements of tumor hypoxia. Methods: Twenty-eight patients receiving RT-CT for cervix cancer underwent weekly magnetic resonance imaging (MRI) scans. Tumor volume was assessed on each of these scans and the rate of regression plotted. A mathematical model of tumor regression was formulated to simulate the relationship between three independent radiobiological parameters, 1) surviving fraction of cells after 2 Gy, SF2, 2) the cell clearance constant Tc, and 3) the cellular proliferation constant Tp. Non-linear regression analysis was applied to fit the MR-derived tumor volumes to the mathematical model and to derive SF2 and Tc values for each patient. These were compared to pre-treatment hypoxia measurements. Results: Initial tumor volume ranged between 8 and 209 cm3. Relative reduction in volume during treatment was 0.02 to 0.79. Simulations using representative values of the independent biologic variables derived from the literature showed SF2 and Tc to strongly influence the shape of the volume response curves. Non-linear regression analysis yielded a median SF2 of 0.71 and median Tc of 10 days. Radioresistant tumors (SF2 >0.71) were significantly more hypoxic at diagnosis (p=0.02). Conclusion: Based on serial MR imaging during treatment, a marked variation in cervix tumor regression is seen from patient to patient. Through our radiobiological model, tumors can be classified as radioresistant or radiosensitive, which correlates with hypoxia [Table: see text] No significant financial relationships to disclose.

Membrane Crystallization and Membrane Condenser: Two Membrane Contactor Applications

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Frappa M ◽  
◽  
Li X ◽  
Drioli E ◽  
Macedonio F ◽  
...  
Keyword(s):  
Membrane Distillation ◽  
Current Status ◽  
Water Recovery ◽  
Membrane Processes ◽  
Gas Streams ◽  
Development Direction ◽  
Salt Crystals ◽  
Industrial Gases ◽  
Pre Treatment ◽  
Application Fields

In recent years different new membrane processes have been designed and developed. In this paper two innovative processes (i.e., membrane condenser and membrane crystallization) will be described and discussed. Membrane crystallization can be used in desalination in combination with membrane distillation and pressure driven membrane processes (such as nanofiltration or reverse osmosis) to achieve high recovery factor combined to salt crystals production.The innovative membrane condenser can be used for the selective recovery of evaporated waste water and contaminants from industrial gases. This process can be also used for pre-treating gas streams that require further separation for the recovery of a defined species (such as pre-treatment of flue gas when used for CO2 capture, biogas for bio methane production, etc.). The current status, the separation principle, the utilized membrane materials and membrane configurations, and the application fields are described and discussed. The future development direction of these two processes is also given. Keywords: Membrane Crystallization; Membrane Condenser; Water recovery; Membrane Technologies;

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