Water Chemistry - Science topic

After the preparation of Graphene Oxide (GO), from modified Hummers method there are two recommended washing steps: (i) with HCl and (ii) then with de-ionised water. Is it advisable to make the PH to neutral by addition of base like NaOH instead of washing with de-ionised water several times to remove acid  >??? 

According to the pourbaix diagram of Fe(2+), it should be dissolve in pH<6, but it is solid even in pH=1. I realy dont know what is the reason.

I am currently synthesizing membranes for drinking water treatment and would like to use non-toxic solvents such as or better than Ethyl lactate. If you have done any research in this field or you know of any compound that I can use, kindly provide me with that information. 

I want to estimate/calculate free CO2 in a freshwater lake. I have a dataset containing pH, DIC and a number of other parameters, both physical and chemical. But I do not have alkalinity.

I have already explored the answers given here: https://www.researchgate.net/post/How_do_I_convert_pH_values_in_CO2_concentration

But I haven't managed to find a solution therein and would be grateful if someone could point me in the right direction.

Here are the parameters I have:

soluble reactive phosphorus, total phosphorus, soluble phosphorus, nitrate, ammonium, dissolved nitrogen, total nitrogen, total silica, DIC, DOC, TOC, soluble reactive silica, chlorophyll a 1, chlorophyll a 2, chlorophyll a mean, water temperature, conductivity, depth, specified depth, pH, turbidity, phycocyanin, oxygen saturation, oxygen concentration, secchi depth

One of the system dont have algal removal facility and the main treatment unit is slow sand filter . within a week we were observed floating slime and afterwards surface of the water fully covered by the slime and greenish algae, treated water also showing diurnal variation. how to control the algae without any alteration in the system  ? system capacity is around 2000m3/day. 

I am trying to remove phosphate from wastewater sample and also recover them. Is there any material that only absorb phosphate from water? Therefore, which natural material should be appropriate to use as absorbent?

Hi,

I'm looking to do a study utilizing a pH sensor for soil pH measurments, among other variables. Essentially i want to create a embedded system that automatically takes pH soil measurments of a pot from several angles(4 or 8 points around 360 degrees) and depths, to get a more complete understanding of pH across the pot soil profile.

Reading up about soil chemistry, soil pH measurments and how different pH sensors work i understand that it's quite complex. Initially using a mechanical sensor arm take either in situ soil pH measruments, or take out a small sample(done by the arm) and create soil suspension to measure on.

What complicates things quite quickly given the nature of pH measurments with pH electrodes when it comes to necessary procedures for storage, cleaning and measurment(in situ would be preferable). ISFET sensors would be great for this application they can be stored dry, easier to maintain etc(from what i've read), but they are hard to come by if not expensive.

The idea of measuring pH of soil water drainage from different points across the pot would simplify things alot, the arm and mechanical measurment mechanims could be excluded from the design.

However i can't find littarture or articles covering the relation between soil pH and soil water pH in a clear way. Thinking about it, it would be logical to assume that pH from extracted soil water, would for most soils correlate strongly with pH of soil, but not be exact to soil pH of the same spot.

Best regards,

The same water samples were filtered at 0.45 µm and 0.02 µm, using respectively Whatman® membrane filters nylon and Whatman® Anotop® 10 syringe filters. The water samples were kept in plastic bottles, and iron and aluminium were measured using ICP-AES. Iron concentrations are, as it should, higher in 0.45 µm than in 0.02 µm filtered water. However, aluminium concentrations are higher in 0.02 µm filtered water.

How would you explain this result for the aluminium? Could a sample be contaminated and, if so, which one would it most likely be (0.45 µm or 0.02 µm) and where would the contamination come from? Could colloidal aluminium adsorb on the plastic bottle used for storage?

Excess of fluoride content in drinking water (more than 1.5mg/L) sourced from inland water bodies causes dental fluorosis and skeletal fluorosis. Although reverse osmosis (RO), electrodialysis, and distillation are available for deflouridating inland water bodies. However am not sure that how effective these methods can be used to deflouridate groundwater. I would like to hear some suggestions on the mechanisms effective at deflouridation of groundwater.

It's silly, but I want to make sure that I am not changing the pH and ORP when I dilute my solution

We are setting up a water filtration system for our bivalves hatchery, the water should be pristine (clear) & clean for to be use in operation.

Seawater was pump directly from the sea, into our sedimentation pond (earthen), then pump into the holding tank in the hatchery that undergo filtration via sand filters.

The water have a slight yellow tint, the colour is very obvious in large volume. Hence, we thought to remedy via chlorination (domestic Clorox) and ozonating the water.

But, instead of purifying the water, it became more orangey-tint, and it stained the water container.

suspect for high concentration of irons, so sent the water from both pond and hatchery for analysis, but the iron level is normal (0.03-0.06 mg/L)

any expert or experiences individual know what/why this occurring and how to remedy the problem?

Please, can you suggest a high graphical resolution software for creating hydrogeochemical graphs, especially for Gibb's diagrams?

Hello all,

i am new to water chemistry, i have been looking at trends in the water chemistry parameters, and found there is significant decreasing trend in Stream-water temperature, Ca, Mg, Na, and chloride along with discharge both in the monsoon and non-monsoon seasons.

Like From Jan 1994, Jan 1995, Jan 1996...... Jan 2018 (for Non-Monsoon period) Sept 1994, sept 1995, sept 1996...................Sept 2018 (Monsoon period)

Note- watershed (1000 km2 drainage area, Western Ghats, India) is free from dams and other water structures.

What could be possible drivers of trends in the above parameters?

Please provide your valuable suggestions.

Thanks in advance.

Regards

Rajat

I would like to use calcium chloride in the irrigation system but not sure the most soluble form?

Calcium chloride dihydrate

Calcium chloride hexahydrate

Calcium chloride granules

The anode and cathode surfaces are considered or just the anode?

I want to treat sliced carrots in ozonated water. The dosage i will apply is 1uL/mL i.e. 1 uL ozone/mL oxygen gas. If somebody could please help me with the amount of water I should take.

Hello,

I have to prepare a solution of 100ml 0,5N Phosporic Acid  from 85% Phosporic acid,that I already have.

Following the formula W= XEV/1000, I would have the following:

XEV/1000= 4,8985 gm  --> (being X=Molarity or Normality; E=97.97; V=100)

Vol= 4,8985/1,685= 2,907 ml --> (V=mass/density)

Would it be proper to add this volume of 85% Phosporic acid and water up to the desired final volume of 100ml?

Thanks a lot,

Miguel

Dear to whom it may concern,

Based on ChemAxon, I calculated pKa values of Acesulfame as follows:

Because I would like to convert Acesulfame Potassium into Acesulfame, I intend to use a stronger acid such as HCOOH or HCl than Acesulfame to do this conversion.

I am wondering whether this approach will really work or not.

May you please share your opinion with me?

Thanks in advance,

Quynh Khoa Pham.

We use the tried and true ammonium molybdate / potassium antimonyl tartrate react in acid medium with reduction to an intensely colored molybdenum blue by ascorbic acid.

The resulting solution is supposed to be colorless, but no matter what we try, the solution always turns yellow. The problem appears to be the ascorbic acid. We tried refrigerating it, storing it under vacuum, and the campus chaplain tried to perform an exorcism. Nothing worked.

I did have some luck recrystalizing the ascorbic acid but is there a better way?

The EPA method mentions using a small amount of acetone as a preservative

Thank you

Kevin

I have reviewed in the literature "experimental correlations" of Ra with species (calcium, sulfate, etc). However, the linear adjustments are not the most satisfactory in analytical terms. Are there other ways of correlations ionic species?.

Greetings. Ender

Microbrewing continues to expand across the globe with many US communities utilizing breweries as new social venues to meet-greet and participate in social activities. What do you perceive as interesting research questions related to brewing science as well as the interaction and impact to local communities?

We measured several water chemistry parameters (nitrate, DOC, EC, pH, Tre..) every 50m in the stream network of six headwater catchments.

Has anybody done that before, and what geostatistical method would you use to describe/interpret the spatial patterns we observed?

during chemical analysis of groundwater of an industrial area, we found the concentration of fluoride in the range 0.15-0.32 mg/L, the pH of the water was found to be in the range 7.5-8.2 and bicarbonate alkalinity were found in the range 1000-5000mg/L.

please help me in  this regard

Important physical and chemical parameters of water are influenced by temperature, pH, salinity, dissolved oxygen, and redox potential. Others are total suspended and dissolved solids, nutrients, heavy metal contaminants, etc [1].

Conductivity or electrical conductivity (EC) and total dissolved solids (TDS) are frequently used as water quality parameters. The value of EC and TDS are correlated. EC is the measure of liquid capacity to conduct an electric charge. Its ability depends on dissolved ion concentrations, ionic strength, and temperature of measurements. The dissolved ions concentration is usually measured as TDS. EC can be measured easily and inexpensively in situ by a portable water quality checker. On the other hand, the analysis of TDS is more difficult and expensive as it needs more equipment and time. Researchers have done various investigations to find out the precise mathematical correlation between these two parameters, so TDS concentration can be simply calculated from the EC value. The correlation of these parameters can be estimated by the following equation:

TDS ( mg L ) = k x EC ( μS cm) (1)

The value of k will increase along with the increase of ions in water. However, the relationship between conductivity and TDS is not directly linear; it depends on the activity of specific dissolved ions average activity of all ions in the liquid, and ionic strength [2].

The conductivity of ions in water depends on the water temperature. Ions move faster when the water is warm. Hence, the apparent conductivity is increased when the water has a higher temperature [3].

It works pretty well but conductivity is temperature-dependent. The conductivity of ions in water depends on the water temperature. Ions move faster when the water is warm. Hence, the apparent conductivity is increased when the water has a higher temperature [4]

Temperature is also important because of its influence on water chemistry. The rate of chemical reactions generally increases at higher temperatures. Water, particularly groundwater, with higher temperatures can dissolve more minerals from the surrounding rock and will, therefore, have a higher electrical conductivity [5].

If it is exactly the same source of water, and no evaporation has occurred, TDS will be the same. If some evaporation has occurred, then the solute is more concentrated, so TDS is higher. As temperature increases, both the water molecules and the dissolved ions become more mobile and the conductivity increases, so even for exactly the same sample at different temperatures, with no evaporation to concentrate the solids, the reading will be different. It is because of the measurement method. As long as the temperature and composition remain the same, the conductivity of the water will not change. So the rate of diffuse is directly proportional to TDS [6].

Two things are at play when you measured your water’s TDS: first, warm water evaporates faster than cooler water. This leads to the minerals being concentrated. Thus, higher TDS reading. Second, the way the meter operates is by measuring and calculating based on the specific conductance of the water. It is measuring the salt content. Warmer water has higher conductance than cooler water. Again, higher conductance equal higher TDS. Temperature changes will often change the conductivity of various materials, and this may be interpreted by the meter as a higher reading [7].

Stirring a solute into a solvent speeds up the rate of dissolving because it helps distribute the solute particles throughout the solvent. For example, when you add sugar to iced tea and then stir the tea, the sugar will dissolve faster

The rate of dissolving of a solute in a solvent is faster when the solute and solvent are stirred, the solvent is warmer, or the solute consists of smaller particles with more surface area. If there is turbulence or there is the velocity in water then there is an increase in the rate of solubility and TDS will be increased [8].

Surface water (velocity containing water) supplies such as lakes and rivers that are exposed to the sun are richer in organics may or may not have biological oxygen demand. Surface waters also contain more fine silt and more dissolved minerals because they have had more water movement and been exposed to more minerals. Water from deep wells is almost always colder than surface waters. It has been filtered naturally through layers of stone and thus has fewer minerals. The definition of the deepwater well is one that does not contain organics. Shallow wells often contain organics [9].

Increasing the temperature increases the solubility of solids and liquids.

The solubility of solutes is dependent on temperature. When a solid dissolves in a liquid, a change in the physical state of the solid analogous to melting takes place. Heat is required to break the bonds holding the molecules in the solid together. At the same time, heat is given off during the formation of new solute-solvent bonds.

CASE I: Decrease in solubility with temperature: If the heat given off in the dissolving process is greater than the heat required to break apart the solid, the net dissolving reaction is exothermic (energy is given off). The addition of more heat (increases temperature) inhibits the dissolving reaction since excess heat is already being produced by the reaction. This situation is not very common where an increase in temperature produces decrease insolubility.

CASE II: Increase in solubility with temperature: If the heat given off in the dissolving reaction is less than the heat required to break apart the solid, the net dissolving reaction is endothermic (energy required). The addition of more heat facilitates the dissolving reaction by providing energy to break bonds in the solid. This is the most common situation where an increase in temperature produces an increase in solubility for solids.

Have the aqueous waste which contains 20-75 ppm of cyanide waste. Need to bring down the cyanide level to 0.1 ppm. Have tried some conditions but were  able to get upto 8 ppm.

Kindly suggest any robust method to achieve cyanide level below 0.1 ppm.

Hi all,

I'm gonna study the impacts of the rise of production wells numbers (for irrigation purpose), LU/LC changes on the groundwater in a flat area where  river branch, main canal and many irrigation and drainage canals run through. The main aquifer in this area is recharged from the surface water (i.e. river branch, main canals, and irrigation and drainage canals) and the infiltration of excess irrigation water. The aquifer is semi-confined to phreatic (leaky aquifer). In addition, it is highly conductive with hydraulic conductivity ranging from 80 to 100 m /day, that is because it consists mainly of sand and gravels with clay lenses. Unfortunately, there is no a systematic monitoring for the water level, water chemistry or actual management for this aquifer. There are too many research works in different ways (e.g. geologic, hydrogeology, hydrogeochemistry,..etc.) have been done. There is no actual estimation for recharge quantity, monitoring for the impact of the anthropogonic activities on this aquifer. I have studied some samples from  3 wells, 2 shallow wells (25 m deep and 2.5 inches diameter) and one deep (65 m deep and 8 inches diameter). One of the two shallows is hand pump tube well and located close to the urban area (in agricultural land) with peizometric level, 10.4 m  and nitrate concentration, 6 ppm. And the second shallow well is being pumping using pump machine and located in urban area, north east the first shallow well with approximately distance 1 km long, with peizometric level of 10.3 m and nitrate concentration, 100 ppm. The deep well (the third one) is located north the second shallow well with distance 1 km long, peizometric level is 10.3 m and nitrate concentration is 3 ppm, which located at agricultural land. The second shallow well and the deeper one are both located close to drain canal with its nitrate concentration not more than 40 ppm as literature's result . I believed that the highly pumping rate is the main factor that gives the high nitrate value for the second shallow well. I really need to study the large area with many urban areas surrounded by agricultural lands, and find out the pollutions anomalies. I will measure CFCs as indicator of the recent recharge, GMS model to simulate the nitrate transport and the future prediction of its concentration, main ions, N15  to find the source of the nitrate and total coliforms . I really interested to find a valuable solutions for such problem. So if some one interested to help me in such study or give me advises, ideas and recommendations to how can I study the nitrate pollution anomaly, estimate and quantify the groundwater recharge, and study the impacts of the high density of wells (for irrigation purpose) on the quality and quantity of the groundwater in this area, I will be greatly appreciate.

Dear all,

I would like to collect soil water for isotopic and chemical analysis, Soil types found in my area are clay, clayey loam and gravelly clay. Can anybody suggest what is appropriate method of collecting soil water upto 1-3 meters in these soil types?

Thanking You all in advance..

Warm Regards

Rajat

In one of my experiment, some adsorbent is used for the removal of heavy metals from water. Now I want to recover the metal from residues.

As you know, one way to tackle water & wastewater pollution is synthesize adsorbents which their raw material obtains from polluted sources (Take synthesize refinery sludge-based activated carbon to remove hydrocarbon pollutants from refinery wastewater as an example).

- It is an attractive and challenging approach, isn't it?

- What is your opinion about this approach?

- And what are other ideas, examples, and methods -based on pollution to solution- that are interesting to do some research on them?

I am conducting an adsorption test (of Cr6+) on an adsorbent.

I did the adsorption tests without background electrolyte(BE) by just dissolving the Cr source in Milli-Q water. I also did a test with different background electrolytes (0.01-.1M NaCl, KCl, CaCl2, NaNO3).

Can somebody with experience on adsorption tests enlightment me. Thanks a lot!

Ex: Think total hardness is 200ppm. Total treated water requirement is 5000L/day.

Then how calculated the

a) Softener vessel size?

b) Required resin volume?

c) Salt regeneration time?

d) Dosage of salt?

The impact of soil erosion on water quality/chemistry appears to be well-known. However, the impact of water chemistry on soil erosion seems not to be well-known.

Bottle drinking water contained many floc. What is the reason? This water produced from fully automated systems.

In environmental chemistry, the chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in water. Most applications of COD determine the amount of organic pollutants found in surface water (e.g. lakes and rivers) or wastewater, making COD a useful measure of water quality. It is expressed in milligrams per litre(mg/L), which indicates the mass of oxygen consumed per litre of solution. But how could we estimate the amount of Organics by the COD of waste water? I wanna set up a calculation relationship between the organics content and wastewater COD.

Different groups favor different methods; I would greatly appreciate more input on the debate. Assume all bottle types are cleaned thoroughly and samples are being analyzed in the lab for Methylmercuy (MeHg), Total mercury (THg), both filtered and/or unfiltered. Other considerations: remote work, trace-level contamination, freezing vs. acidification.

In a unique condition, hot springs and cold springs are found to occur at close proximity. It is observed that the springs has similar chemical composition. What could be the reason(s) for this?

Water quality also can have impact on irrigation equipment. Let's talk about possible impacts of water chemistry on irrigation equipment.

If there is an intrusion of sea-water into freshwater aquifers, whether the cat-ion exchange is sufficient to account for the change in water chemistry?

We are trying to quantify synchrony in water chemistry variation among several hundred sites. For each site we have a time-series of concentration. We'd like to quantify the overall temporal covariance (are concentrations going up and down at the same time) among the sites and are interested in different statistical approaches to to do this. The different chemistry parameters have very different absolute concentrations (e.g. 1-100 ppm for carbon, 0.001 to 1 ppm for phosphorus) so a relative metric is necessary. We have done this previously with the average pairwise scaled covariance (), but there may be a more elegant method . . . Thanks!

Which one is the best method of degassing, is it HPLC (Waters) in-line degasser? or manually degass with sonicator? Please give some facts and reasons.

I want to estimate the sulfide concentration in the wastewater. What is the sensitivity of methylene blue method (detection limit - how much ppm?, maximum how much i can quantify the sulfide?). Please anyone suggest easy and reliable method for sulfide estimation in the wastewater containg high sulfide concentration.

I am trying to use RO modelling software but not getting recovery more than 40%. Can anyone suggest how to increase recovery with such a highly concentrated feed? My water chemistry is not completely balanced I guess. But dont have anything other than ammonia in my feed. I want make ammonia rich product and use it. I am using winflows software for modelling. Please help.

my company puts its specifications at a range of 350 -1000ppm but all the diocuments I read give me 150 - 350ppm yet I have always found it difficult to get that specification of 350 and above?

and if i try addind caustic the PH of course shoots to above 12 < what should I do?

Best protocol to measuring soluble phosphate in NBRIP broth medium

All

Should there be any differences in water chemistry of a stream site (pool/waterhole) once flow/discharge ceases? At depth?

As the flow ceases and the water evaporates and stratifies, there will be differences in ph, DO and temperature at depth, but does this transpire to significant changes in other water chemistry parameters?

Alos, I have water chemsitry data coleected from the surface at a number of sites over time with varying flow/discharge - down to zero flow. I want to test to see if there are significant differences based on the discharge and time since flow ceased. I was considering using PCA to explaore the relationship between flow and time since flow. Any other suggestions?

I am looking on calcium carbonate precipitation in seawater and would like to know how (or to what extent) anions (PO₄^3-, CO_3^2-, SO₄^2-) and cations (Ca²⁺, Mg²⁺) draw water molecules into the calcium carbonate crystals lattice during precipitation. Also, how stable is the bonding between these ions and the water molecules?

We recently aproved a grant for a project, and now we are searching the best equipment. Besides the already mentioned parameters, analysis of water hardness, nitrates, nitrites and phosphate would also be welcome. Some collegues told me already about equipments from Horiba and Hanna. Other suggestions?

For studying water chemistry, phytoplankton analysis or microbial analyses? 

Thanks in Advance for the valuable answers. 

sincerely

Anila Ajayan 

When pH of the solution change ORP value also change or not. What happen the pH of water when ozone is dissolved into water

Results has been over 7 even with hardness in conformity.

Every columns and filters are new and the ion exchange resin is 50% anionic and 50% cationic.

THe sample is a lake with 23725 µS/cm conductivity

pH 8,85

alcalinity   178,20 mg CaCO3/L

size more or less 28 x 15 microns

i think that perhaps  could be a raphydophyceae ( Chattonella ?) or perhaps a Chromulina ???

In photo m1 one of them is eating a Amphora.

Thanks in advance, any idea can help me

Maria 

Coagulation-flocculation 

Water treatment 

Wastewater treatment 

Alum

Natural coagulants 

Zeta potential 

Coagulation-flocculation

Water treatment 

Wastewater treatment 

Neutralisation 

Is there any method to quantify the chlorine ion in water?

Dear fellow researchers, I am Master Student of Vienna University of Life Science and Im working on MFI vs SDI project. I am stuck on the curve calculation and I am kindly asking how to do so. On excel I have the values of litters the filter have filtered and the second of which it required to filter. So to get the s/L vs L curve I am dividing the seconds by the litters ( without no minus V2-V1) and if I get the curve it has a sharp point which looks nothing like the previous research works. The water is normal brine water with 250 mg/l TDSMFI

Specifically arsenic bearing liquid discards. I have the information on solid wastes.

Hello.I hope you have a good day. I'm using cationic resin form H+ for reducing the hardness and EC(electrical conductivity) of water.now in my experiments the hardness of water has decreased ,but EC has increased. To what extent H+ ion can affect EC in water? I want you to suggest me a solution that how can I reduce EC ?i appreciate it.

Hello every one.

We are working on a project for some industry and we have treated its wastewater with electrocoagulation flotation (ECF) technology successfully. However because of that the final water from wastewater plant will be recycled as a process water, at the end of the wastewater system there is a reverse osmosis. The effluent from the ECF process has oil and grease= 7.5 mg/l and the oil content reduces to 4 mg/l with the aid of active carbon filter but this rate of oil is harmful for the RO. I need a process to remove this amount of oil to 0.1 mg/l (the limit for dissolved oil in water to enter RO) which process do you suggest to me!?

P.S.: 1-DAF (dissolved air flotation)can not be used since its mechanism is the same as electrocoagulation so it will not reduce any further oil.

2-Ultrafiltration is not favored because only ceramic UF should be used (because of the oil) so it will be expensive especially for treating it from 4 mg/l to 0.1 mg/l!

I appreciate your assistance in advance.

I have some test results for Chromium (totals and dissolved) and the dissolved levels are higher than the totals How is this possible even though all quality controls are acceptable ? that's mean 100 % of chromium is in dissolved state?

I have an equation to calculate the amount of coagulant required to remove colour from water samples which uses Hazen units. I have absorbance values which I would need to covert to Hazen units, anybody know of an easy way to do this

I wish to perform bulk electrolysis of samples which may take some time and don't want microbial activity to alternate the results.

Here i use iron nanoparticle in textile waste water to degtader DOM. where BOD, COD and TOC also reduced.

Are there any publications with details of where BAF units are installed in France? (or The Netherlands or Belgium, but given size France should have more sites).

Is there any literature that has reported the partition coefficient of boron (H3BO3) in the reverse osmosis (RO) membrane? The partition coefficient is the ratio of the boron concentration in the membrane and the boron concentration in solution. Thank you!  

From Na2SO4 high concentration sulfate wastewater i would like to remove sulfate by gypsum precipitation.  I have tried many test, using lime milk, temperature, dilute solution and still no gypsum precipitation. Any clue? 

Dear all, regarding portable pHmeter, do you have any brand recommendation? I have seen the Mettler Toledo and Hanna. Any of you have experienced any of those? We will use the equipment to adjust pH of solutions and culture media.

Thanks

During the testing of surface water samples, PI values are lower than the TOC values. 

If the raw water is fairly good quality overall but high TOC, which alternative would be more cost effective to control DBP. 

The total hardness of a given sample of water is 136 mg/l

The M alkalinity of the same sample is 267 mg/l

Please show how to calculate the values for carbonate and non-carbonate hardness from the above values.

Is there any pathogenic organism or smelling effect formed in fresh water yield while using wick or sponge material in solar still desalination

Just wondering, how to add HCO3 without raising sodium to the irrigation system ? what is best source of HCO3 for irrigation? 

Although atrazine is almost neutral.

The water solubility of atrazine is 34.7 mg/L measured in fresh water at pH 7 at 26°Ϲ (Ward & Weber 1968). In your study, The water solubility of atrazine is 60 mg/L measured in fresh water at pH 6 at 25 °Ϲ . Is the difference due to the pH changing?

 In your study, The water solubility of atrazine is 60 mg/L measured in fresh water at pH 6 at 25 °Ϲand 50 mg/L measured in seawater at pH 8 at 25 °Ϲ . Both the pH and salinity are different. 

I would appreciate with your reply.

Hey, I would appreciate if somebody help me “what is the Max permissible limit for Na+, Ca2+, Mg2+, K+, Ca2+, Cl−, HCO3−, in drinking and irrigation water according to WHO standard. Thanks

I want to estimate dissolved oxygen in PBS at 37°C, at different pressures using Henry's law. I can find data for water at different temperatures, or for PBS at 25°C, but no info for PBS at 37°C. Does anyone know the Henry's constant for PBS at 37°C ? Or would you advise another calculation method ?

For mass balance and design of waste water treatment plant.