Contaminant Transport Hydrology - Science topic

What can we use as a non-reactive tracer for soil ground water for monitoring different reactions like denitrification?

In sorption and leaching exprimnets one mostly uses 0.01 M CaCl2 (see also OECD guidelines). This is because a) soil never contains simply water but always a solution of different salts. b) Agricultural soils typically have soil pH >4.5. Under that conditions Ca ions largely dominate the solution. As a consequence of a) and b) 0.01 M CaCl2 is a perfect surrogate of soil solution.

Dear Sir.

Конечно, это правильная мера. В проекте на бурение  после цементации затрубного пространства верхней колоны труб целесообразно предусмотреть проверку герметичности.

Угрозу второму водоносному горизонту представляют скважины, которые бурятся стихийно населением с использованием примитивных средств, когда не предусматривается изоляция верхнего горизонта (одна труба). С этим можно бороться только широким распространением информации о зря потраченных средствах на такие скважины. 

Good luck

GEO-STUDIO seems to be geotechnical and geomechanical software, and I am not sure you can use this for solute transport. MODFLOW (not MUD FLOW) is a groundwater flow model http://water.usgs.gov/software/lists/groundwater or http://www.groundwatermodels.com/ESI_Software.php or http://www.novametrixgm.com/groundwater-modeling-software/visual-modflow-flex which can be coupled with another model that simulates solute transport (see above links).

For soil water modeling, you need a model that solves for flow and transport in partially water saturated conditions. The Hydrus model solves soil water flow and is coupled with solute transport codes, which make it appropriate for soil water and solute transport modeling http://www.pc-progress.com/en/Default.aspx?hydrus-1d and http://www.pc-progress.com/en/Default.aspx?hydrus-3d .

Dear Lijo,

In addition to the compounds you have mentioned in your very interesting question I list some publications that describe other materials with or without those you mentioned:

1-Journal of Membrane Science

Volume 471, 1 December 2014, Pages 381–391

 

Thin-film composite membranes formed by interfacial polymerization with natural material sericin and trimesoyl chloride for nanofiltration

Choumou Zhoua, b, Yalan Shia, b, Changsheng Suna, b, Sanchuan Yua, b, , Meihong Liub, Congjie Gaoc

Highlights

 •TFC membranes for nanofiltration were prepared via IP between sericin and TMC.

Sericin–TMC composite membrane has smooth and thin selectively skin layer.

•

Membrane with a MWCO of 880 g/mol achieves a pure water permeability of 11.9 l/m2 h bar.

•

Rejection order of the TFC membrane is MgCl2<MgSO4≈NaCl<Na2SO4 at neutral pH.

•

Sericin–TMC composite membrane possesses better antifouling property than NF270.

 

Abstract

Novel flat-sheet thin-film composite membranes for nanofiltration were fabricated through interfacial polymerization of natural polymer sericin and trimesoyl chloride (TMC) on porous polysulfone support membrane. The preparation parameters including pH of aqueous phase, reaction time, curing temperature, curing time, sericin content and TMC concentration were investigated. The properties of the resultant membrane were characterized in terms of surface chemical structure, morphological structure, surface zeta potential, pure water flux, molecular weight cut-off (MWCO), pore size and rejections to different solutes including electrolytes and organic anionic dyes. It was found that the obtained sericin–TMC composite membranes had smooth and amphoteric surfaces with an isoelectric point at pH about 4.1. The membrane with a MWCO of 880 g/mol had a pure water permeability of 11.9 l/m2 h bar and exhibited a salt rejection order of MgCl2 (22.5%)<MgSO4 (40.5%)≈NaCl (40.8%)<Na2SO4 (95.4%) at neutral pH. The dye removal tests indicated that the obtained membrane could effectively reject the organic anionic dyes at neutral pH with good anti-fouling property, especially for the dyes with relatively higher molecular weight and/or more negative charge. Moreover, compared with the commercial nanofiltration membrane NF270, the developed sericin–TMC composite nanofiltration membrane possessed better antifouling property.

2-Desalination

Volume 288, 1 March 2012, Pages 98–107

 

Thin-film composite membrane formed by interfacial polymerization of polyvinylamine (PVAm) and trimesoyl chloride (TMC) for nanofiltration

Meihong Liua, b, Yinping Zhenga, b, Shi Shuaia, b, Qing Zhoua, b, Sanchuan Yua, b, ,Congjie Gaoc

 

 Abstract

This study focus on the preparation and nanofiltration properties of a novel thin-film composite polyamide membrane formed by the interfacial polymerization of polyvinylamine (PVAm) and trimesoyl chloride (TMC) on a porous polysulfone supporting membrane. The fabrication of the PVAm–TMC composite membrane was conducted by studying preparation parameters including reaction time, pH of the aqueous phase solution, reactant concentration, as well as curing temperature and time. The properties of the resultant membrane were characterized in terms of morphological structure, surface zeta potential, pure water flux, molecular weight cut-off (MWCO) and rejections to different solutes including electrolytes and organic dyes. The results showed that the optimized composite membrane had a smooth and amphoteric surface with an isoelectric point at pH about 6.5, a MWCO of around 650 Da, a pure water permeability of about 8.5 l/m2 h bar and good long-term stability. The rejection order of the membrane to inorganic salts changed from MgCl2 < NaCl < MgSO4 < Na2SO4 at pH of 7.0 to NaCl < Na2SO4 < MgSO4 < MgCl2 at pH of 6.0. The dye removal tests also indicated that the obtained membrane could effectively reject the negatively charged organic dyes at neutral pH with good anti-fouling property, especially for the dyes with relatively higher molecular weight and/or more negative charge.

Highlights

► TFC membrane for nanofiltration can be prepared through interfacial polymerization of PVAm and TMC. ► The TFC membrane has a MWCO of 650 Da and a pure water permeability of 8.5 l/m2 h bar. ► The rejection order of the TFC membrane is MgCl2 < NaCl < MgSO4 < Na2SO4 at pH of 7.0. ► The rejection order of the TFC membrane is NaCl < Na2SO4 < MgSO4 < MgCl2 at pH of 6.0. ► The TFC membrane can effectively reject anionic dyes at neutral pH with good anti-fouling property.

3-This is a very interesting publication on "Simulation of Thin Film Membranes Formed by Interfacial Polymerization" published in Langmuir, 2010, 26 (1), pp 299–306; DOI: 10.1021/la9024684

Interfacial polymerization is widely used today for the production of ultrathin films for encapsulation, chemical separations, and desalination. Polyamide films, in particular, are employed in manufacturing of reverse osmosis and nanofiltration membranes. While these materials show excellent salt rejection, they have rather low water permeability, both properties that apparently stem from the rigid cross-linked structure. An increasing amount of experimental research on membranes of different chemistries and membrane characterization suggests the importance of other factors (such as unreacted functional groups and surface roughness) in determining membrane performance. We developed a molecular simulation model to qualitatively study the effects of various synthesis conditions on membrane performance, in terms of its estimated porosity and permeability. The model is of an interfacial aggregation process of two types of functional monomers. Film growth with time and structural characteristics of the final film are compared with predictions of existing theories and experimental observations.

4- Interfacial polymerization of thin film nanocomposites: A new concept for reverse osmosis membranes

ARTICLE in JOURNAL OF MEMBRANE SCIENCE 294(1-2):1-7 · MAY 2007

Abstract

Here, we report on a new concept for formation of mixed matrix reverse osmosis membranes by interfacial polymerization of nanocomposite thin films in situ on porous polysulfone supports. Nanocomposite films created for this study comprise NaA zeolite nanoparticles dispersed within 50–200 nm thick polyamide films. Hand-cast pure polyamide membranes exhibit surface morphologies characteristic of commercial polyamide RO membranes, whereas nanocomposite membranes have measurably smoother and more hydrophilic, negatively charged surfaces. At the highest nanoparticle loadings tested, hand-cast nanocomposite film morphology is visibly different and pure water permeability is nearly double that of hand-cast polyamide membranes with equivalent solute rejections. Comparison of membranes formed using pore-filled and pore-opened zeolites suggest nanoparticle pores play an active role in water permeation and solute rejection. The best performing nanocomposite membranes exhibit permeability and rejection characteristics comparable to commercial RO membranes. As a concept, thin film nanocomposite membrane technology may offer new degrees of freedom in tailoring RO membrane separation performance and material properties.

5-The attached  file is a suggested experiment entitled:

 Interfacial polymerization of Nylon 6,10

6-Progress in Interfacial Polymerization Technique on Composite

Membrane Preparation

W.J. Lau+ and A.F. Ismail

Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310

Skudai, Johor, Malaysia.

Abstract. The concept of interfacial polymerization (IP) has been known for more than 45 years since it was first reported by Mogan in 1965. Since then, there have been intensive and continuous efforts from academic and industry to further improve performances of composite membranes prepared using IP technique. Novel/modified procedures on IP process have been recommended with the aim of improving interfacially-synthesized polyamide layer through forming a defect-free selective skin onto membrane and establishing a strong adhesion between top selective layer and bottom microporous substrate membrane.

Previous results indicated that enhanced properties of composite membrane could be produced using modified IP process. More attention however should be paid on composite hollow fiber preparation in order to make the membrane full use in industrial applications. 

7-Thin Film Composite Nanofiltration Membrane Formed by Interfacial

Polymerization

Dihua Wu, IPR Symposium, University of Waterloo, ON N2L 3 G1, Canada

Nanofiltration (NF) is a pressure-driven membrane process between reverse

osmosis (RO) and ultrafiltration (UF) in terms of membrane structure. It generally has a high flux, a high retention to multivalent ionic salts and organic molecules with molecular weights above 300 and a relatively low capital and operating costs. Since Cadotte and his co-workers1,2 fabricated high-flux, high-rejection reverse osmosis membranes by interfacial polymerization, thin film composite (TFC) membranes have become commonly used in industry. Preparation of TFC nanofiltration membranes based on interfacial polymerization is generally using two reactive monomers: a polyfunctional amine dissolved in water (i.e., aqueous reactant) and a polyfunctional acid chloride dissolved in a hydrocarbon solvent (i.e., organic reactant). The two solvents are in contact only at their interface, and this allows the reaction to take place at the interface. By employing this approach, an ultrathin polymeric layer (300 - 400 nm) can be formed and adhered to a microporous substrate, leading to a good combination of water permeability and selectivity.

 Hoping this will be helpful,

Rafik

There may be no specific reason why igneous rocks were used and metamorphic rocks were not used, and it may be that the application of the research was for an area with igneous rocks (without metamorphic rocks). I do not believe there are any specific water-rock interaction differences between igneous and metamorphic rocks. A metamorphic rock is a type of rock which has been changed by extreme heat and pressure. So, an igneous rock can become metamorphic by exposing it to heat and pressure. This heat and pressure typically dissolves and re-precipitates some of the minerals in the rock. So, there are some differences in types and chemistry of the minerals, and the morphology of the minerals may be different, which may impact dissolution. Hope that helps.

YA CONTESTE LA PREGUNTA !!!!!! S. Gómez

As you know, tert butyl mercaptan is volatile with relatively low Kow and aqueous solubility around 2000 mg/L. One would expect it to be susceptible to oxidation. You could determine the amount of oxidant needed by doing a total oxidant demand test of the soil as outlined in 2003 paper by Haselow et al. (Remediation,Autumn, 2003, pp 5-16).  

To remove it from soil, the most effective (and least costly method) would likely be air sparge and soil vapor extraction and I would start by doing that since it will reduce the oxidant demand of the soil (if you later wanted to amend with a chemical oxidant for example). Although the theoretical analysis of potential reactions is important, bench tests of soil samples from the site (using different oxidants) and a field pilot test will be the most effective way to solve your problem and will also provide insight into the theoretical reaction pathways.

To treat the off gas of an air sparge SVE you may want to consider a flame oxidation unit,  UV /ozone or other activated radical-based process. Researchers have also had success with sorption to activated carbon.

We study the feasibility of the project and identify the elements using ArcGIS for developing the DTM and the river system, MODFLOW® for hydrogeological study and COMSOL® for modeling containment. (Fluid-structure interaction)

This is the only work in the laboratory in this field.

Here's one in Germany where the tracer tests lasted over 300 days and exhibits a long tail:

I don't think adding calcium (2+) to sand would increase the net positive charge on sand, because it is unlikely that calcium will attach to sand. Even there is some attachment, it will not be sufficient to increase net positive charge on sand.

If the aim is to increase net positive charge on quartz, you may consider coating iron oxide (positively charged mineral at neutral pH) on sand. There are many methods to coat iron oxide on sand. You can find those here:

Briefly, to coat iron oxide on sand, sand is soaked in iron solution (iron chloride or nitrate). The iron oxide is precipitated on surface of sands by either slowly increasing the pH (addition of NaOH) or heating the solution until it is completely evaporated.

I agree this is an interesting question. I would suggest you look at this trilogie (a paper / comment and repply to comment)

Wood, E. F., Roundy, J. K., Troy, T. J., Van Beek, L. P. H., Bierkens, M. F., Blyth, E., ... & Whitehead, P. (2011). Hyperresolution global land surface modeling: Meeting a grand challenge for monitoring Earth's terrestrial water. Water Resources Research, 47(5).

Beven, K. J., & Cloke, H. L. (2012). Comment on ‘‘Hyperresolution global land surface modeling: Meeting a grand.

WOOD, E. F., et al. Reply to comment by Keith J. Beven and Hannah L. Cloke on ‘‘Hyperresolution global land, 2012.

The papers and the comment show two approches to modeling. Where Wood et al. aims at increasing the resolution and the complexity of the modeling in priority. Keith and Cloke insiste on the need for new formulations.

Those papers show that still many questions remain unaswered (impact of scale on model formulation for example)

Finaly about the size of publications, lets consider that since we are dealing with stochastic processes a large number of generation (or papers) are needed to converge (to find the Graal).