scholarly journals Optimization and Analysis of a Slow-Release Permanganate Gel for Groundwater Remediation in Porous and Low-Permeability Media

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 755
Author(s):  
Jesse L. Hastings ◽  
Eung Seok Lee
Keyword(s):  
Groundwater Remediation ◽  
Colloidal Silica ◽  
Slow Release ◽  
Silica Content ◽  
Nonaqueous Phase Liquids ◽  
Lateral Spread ◽  
Prolonged Release ◽  
Saturated Porous Media ◽  
Column Tests ◽  
Novel Treatment

Dense nonaqueous phase liquids (DNAPLs) like trichloroethylene (TCE) serve as the most common form of groundwater pollution in the world. Potassium permanganate (KMnO4) is a strong oxidant that can quickly destroy DNAPLs into innocuous products. Slow-release permanganate gel (SRPG), a mixture of colloidal silica (CS) and KMnO4, has been recently developed as novel treatment option for dilute and large plumes of DNAPLs in groundwater. The objective of this study was to characterize and optimize gelling and release properties of a SRPG solution in saturated porous media. It was hypothesized that CS and KMnO4 content of the SRPG constrain gelation and release duration. Batch and column tests showed that gelation could be delayed through manipulation of the KMnO4 content. In column tests, silica content had little effect on the gelation lag stage and release rate but influenced duration of permanganate release. Flow tank tests comparing Bindzil 1440 (B-40) SRPGs with pure KMnO4 solutions under varying media conditions demonstrated that the presence of CS enhanced lateral spread and prolonged release duration of the oxidant.

Nano-Silica Reinforced UV-Curable Hybrid Hard Coatings on Polymethylmethacrylate (PMMA) Substrate

2012 ◽  
Vol 557-559 ◽  
pp. 1797-1802
Author(s):  
Xiao Ying Sun ◽  
Jianan Wang ◽  
Jian Zhong Hang ◽  
Lu Jiang Jin ◽  
Li Yi Shi
Keyword(s):  
Colloidal Silica ◽  
Silica Content ◽  
Hard Coatings ◽  
Hybrid Coatings ◽  
Pmma Substrate ◽  
Coating Films ◽  
Pencil Hardness ◽  
Uv Curable ◽  
Silica Suspension ◽  
Inorganic Components

Hybrid sols were synthesized through a combination of hydrolysis and condensation reactions of tetraetoxysilane and γ-Methacryloxypropyltrimethoxysilane together with the addition of a colloidal silica suspension. A transparent, hard UV-curable hybrid coatings based on hybrid sols were prepared in order to improve the scratch and abrasion resistance of PMMA substrate. The effects of the content of colloidal silica suspension on pencil hardness, transmittance, and haze were investigated. The pencil hardness of all coating films in this study can be tuned from 4H to 9H, whereas that of uncoated PMMA substrate is 1H. The higher hardness of the coatings can be attributed to the dense structure induced by the increase of network density with the addition of colloidal silica suspension. Furthermore, it is found that the transmittance of coatings slightly fluctuates between 91.8% and 93.6% with increasing colloidal silica content. These results indicate the good compatibility of the organic and inorganic components.

Injectable silica–permanganate gel as a slow-release MnO4− source for groundwater remediation: rheological properties and release dynamics

2016 ◽  
Vol 18 (2) ◽  
pp. 256-264 ◽  
Author(s):  
S. Yang ◽  
M. Oostrom ◽  
M. J. Truex ◽  
G. Li ◽  
L. Zhong
Keyword(s):  
Rheological Properties ◽  
Pore Water ◽  
Fumed Silica ◽  
Groundwater Remediation ◽  
Slow Release ◽  
Chlorinated Contaminants

A mixture of aqueous KMnO4 solution and fumed silica powders produces a gel that slowly releases a MnO4− oxidant which enhances the removal of chlorinated contaminants from pore water in aquifers.

Effect of Colloidal Silica Contents in the Organic-Inorganic Hybrid Coatings on the Physical Properties of the Film on the Metal Surface

2007 ◽  
Vol 124-126 ◽  
pp. 655-658
Author(s):  
Do Hyun Kim ◽  
Hyung Mi Lim ◽  
Sang Mok Kim ◽  
Byoung Man Kim ◽  
Dae Sung Kim ◽  
...  
Keyword(s):  
Physical Properties ◽  
Colloidal Silica ◽  
Acid Resistance ◽  
Silica Content ◽  
Hybrid Coatings ◽  
Molar Ratio ◽  
Acid Catalysts ◽  
Coating Film ◽  
Corrosion Wear ◽  
Pencil Hardness

The coatings composed of colloidal silica, methyltrimethoxy silane (MTMS), water, and acid catalysts have been prepared with variation of colloidal silica contents from 0 to 20 %. All the coatings were prepared and coated on the aluminum plate under the same condition except the contents of colloidal silica, and the compensating contents of MTMS and water with fixed molar ratio of MTMS and water to be 3. The physical properties were compared in terms of hardness, adhesion strength, corrosion, wear resistance, and thermo gravimetry analysis, etc. The pencil hardness was drastically increased with the addition of 5% colloidal silica particles and was further increased slightly by increase of additional silica. The corrosion resistance of the coating film against alkali solution was improved by increasing colloidal silica content, however, the acid resistance was less affected by the content of colloidal silica.

Optimization of Denser Nonaqueous Phase Liquids-contaminated groundwater remediation based on Kriging surrogate model

2013 ◽  
Vol 8 (2) ◽  
pp. 304-314 ◽  
Author(s):  
Wenxi Lu ◽  
Haibo Chu ◽  
Ying Zhao ◽  
Jiannan Luo
Keyword(s):  
Simulation Model ◽  
Optimization Model ◽  
Surrogate Model ◽  
Groundwater Remediation ◽  
Groundwater Resources ◽  
Optimal Strategies ◽  
Nonaqueous Phase Liquids ◽  
Kriging Surrogate Model ◽  
Aquifer Remediation ◽  
Remediation Process

Spillage of large amounts of Denser Nonaqueous Phase Liquids (DNAPLs) had resulted in serious pollution of groundwater resources throughout the world; a large number of studies had demonstrated surfactant-enhanced remediation is a more effective approach to remediate DNAPLs contaminations. In this paper, the remediation optimization process was carried out in three steps. Firstly, a water-oil-surfactant simulation model had been firstly established to simulate a surfactant enhanced aquifer remediation process. The Kriging surrogate model had been developed to get a similar input–output relationship with simulation model. In the final, a nonlinear optimization model was formulated for the minimum cost, and Kriging surrogate model had been embedded into the optimization model as a constrained condition. What is more, simulated annealing method was used to solve the optimization model and give the optimal Surfactant-Enhanced Aquifer Remediation strategy. The results showed Kriging surrogate model had reduced computational burden and make the optimization model easy to solve, and the optimal strategies gave an effective guide to contaminants remediation process.

Preparation and Patterning of Optical Hybrid Thin Films Based on Photosensitive Polyimide and Monodispersed Colloidal Silica

2008 ◽  
Vol 47-50 ◽  
pp. 654-657
Author(s):  
Yang Yen Yu ◽  
Wen Chen Chien ◽  
Chiung Lin Lai
Keyword(s):  
Thin Films ◽  
Thermal Properties ◽  
Hybrid Materials ◽  
Coupling Agent ◽  
Colloidal Silica ◽  
Silica Content ◽  
Good Resolution ◽  
Hybrid Films ◽  
Fluorinated Polyimide ◽  
Hybrid Thin Films

In this study, optical hybrid thin films were prepared from photosensitive poly(4,4-(hexafluoroisopropyl- idenediphthalic anhydride)-co-oxydianiline) (6FDA-ODA)/MDAE and monodispersed colloidal silica with a coupling agent. It was a combination of the sol–gel reaction, thermal polymerization and spin coating. The coupling agents were 3-methacryloxypropyl trimethoxysilane (MPTMS) or (4-vinylphenethyl)trimethoxysilane (VPTMS). The silica content in the hybrid thin films was varied from 0 to 8.6wt%. The coupling agent and the silica domain were designed primarily for reducing the volume shrinkage and enhancing the thermal properties, respectively. The retention of MDAE in the prepared hybrid films is supported by X-ray photoelectron spectroscopy (XPS). The silica domain significantly enhanced the thermal properties of the prepared hybrid films in comparison with parent fluorinated polyimide. The prepared hybrid materials also exhibited reduced refractive index by increasing the silica content. The results of SEM showed the prepared photosensitive hybrid materials could obtain lithographical patterns with a good resolution. These results indicated that the newly prepared photosensitive polyimide/colloidal silica hybrid thin films had potential applications for optical devices.

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