Extracting mercury from contaminated water

in chemistry chemical waste is pretty much unavoidable and it's very important that you dispose of it safely over the years I've collected a decent amount of waste and I want to show you guys how I'm dealing with it I've decided to make this into a small series so over the course of several videos I'm going to try and cover the major types of waste for today's video I'm going to be dealing with the water-based mercury waste that I've generated over the past couple years a major source of the waste was from the updated Ferro serpent video but a couple other preparations also contributed to it none of the waste can be poured down the drain so I put everything into some four liter water bottles the waste bottles were then stored in a larger plastic container just in case any leaks occurred so over the years what I was left with was two four liter bottles filled to the top and a partially filled 1 litre bottle in the 4 liter bottles I also included paper towel and other things that were contaminated with dissolved mercury this was honestly kind of sloppy and I should not have combined solid stuff with the water as another side note it's important to keep a record of exactly what is in each bottle this can be done by either using a label on the bottle itself or with a separate logbook knowing the contents of the waste is incredibly important and the worst thing that can happen is if you forget what you're even dealing with so I take a look at my records and I see that all of my mercury waste is in the form of mercury tube plus this is extremely important to know because the treatment that I chose will only work for mercury 2 plus and it won't work for the other form mercury 1 plus if my waste was actually mercury 1 plus it would have to be converted to the 2 plus ion by boiling it or exposing it to UV light for a long time the treatment that we'll be doing is called the sulfide precipitation method and the main chemical that I need is sodium sulfide the idea here is to precipitate the mercury as mercury sulphide which is extremely insoluble in water the mercury sulphide can then be filtered off and the water can be discarded in a future video I'll recycle the mercury sulfide back into metallic mercury before we get started keep in mind that this is the most mercury waste I've ever dealt with and it complicated things a little I used my 5 liter beaker and I process the waste in a few separate batches but I should have just used one large container and processed everything all at once the first thing that I wanted to get rid of was the smaller water bottle at the bottom there's a little bit of mercury metal and it's important to keep this separate from the water that I add to the beaker I remove the cap and I pour in as much water as I can without letting any of the mercury fall in the mercury in the bottle is then combined with some other dirty mercury that I have the water bottle is washed a few times with water to get out any bits of mercury that might still remain now the water in this bottle was a little bit high so I poured a bunch of it into the beaker I put on a lab coat and then I place the nylon mesh over the top of the beaker the waste from one of the containers is then filtered through the nylon unfortunately the beaker wasn't large enough to fit everything the stuff that was caught by the nylon was then washed with a little bit of distilled water once they were clean I picked them out and put them in a ziplock bag the nylon mesh was removed and I test the pH using a universal pH paper returns red which indicates that I have a strongly acidic solution sodium sulphide breaks down extremely quickly in the presence of acids so I need to neutralize things before I add it to do this I just used a bunch of sodium bicarbonate in theory it's possible to use other bases like sodium hydroxide but it's very easy to overshoot the neutral point if things get too basic the mercury will start to precipitate as mercury hydroxide and you'll have to add more acid to reduce all vit even if I add way too much sodium bicarbonate the pH shouldn't really go above a value of 8 as the sodium bicarbonate is added it reacts with the acid and forms carbon dioxide gas small additions of sodium bicarbonate can produce a lot of bubbling so it's important to be careful here if too much sodium bicarbonate is added it could bubble out of the beaker which is obviously a bad thing the bubbling also tends to spit some of the liquid out of the beaker so I cover the top with a little bit of plastic wrap as I continue to add the sodium bicarbonate the bubbling became less and less intense I know I'm very close to the neutralization point when the addition of the sodium bicarbonate doesn't cause very much bubbling at the end the bubbling that does occur is just you two being released from the water and there's no reaction actually going on once I was at the neutralization point I continued to add a bunch of excess sodium bicarbonate by adding extra sodium bicarbonate I can make something known as a buffer solution a buffer solution is resistant to changes in pH and in the case of sodium bicarbonate it should hold the pH around 8 this is important for later steps and even if I didn't have to neutralize any acid I still would have added the sodium bicarbonate the amount that I added wasn't exact at all and I just kept pouring it in until it stopped dissolving using a glass stir rod I gave the solution a good mixing and then I tested the pH my pH paper is honestly pretty crappy but based on the color we can see it's between 7 & 9 so it should be around 8 with the solution neutralized and buffered it's time to add the sodium sulphide I measured out about 20 grams in a beaker and then I poured in some water the amount of sodium sulfide that's used here is kind of random because I have no idea how much mercury is actually in the waste I could have figured this out doing a little bit of analytical chemistry but I don't really think it's worth the time if I end up adding too much it's pretty easy to decompose some of it but if I don't add enough I can simply just pour more in from this point on we're going to be working with a sulfide solution so it's going to be really smelly eventually almost all of the sodium sulphite has dissolved and I'm ready to add it to the waste the moment that it's added you can see black mercury sulphide falling out of solution the sodium sulphide is reacting with the mercury two plus ions the four mercury sulphide and the sodium based salt the sodium salt is soluble in water but the mercury sulphide is extremely insoluble so it falls out of solution this type of reaction is generally known as a double displacement I mix things thoroughly using a glass stir rod and then I let it sit undisturbed for about an hour I come back an hour later and I prepare a little bit of sodium sulphide solution I now need to verify that I've added enough sodium sulfide to react with all of the mercury that was present it's really hard to see but some of the mercury sulphide has started to settle to the bottom and there's a thin clear layer at the top using a pipette I take a small sample and I add it to the sodium sulphide the sample that I took does have some mercury sulfide in it but it's clear that more is being generated when it's added to the sodium sulphide what this tells me is that there's still mercury in the solution and I need to add more sodium sulfide a very important wording to make though is that you can't use too much sodium sulfide if too much sodium sulfide is present it will form a water soluble complex with the mercury sulphide and Reda's all vit this is only really an issue with concentrated sodium sulfide solutions so as long as a crazy excess isn't added it should be okay on top of this my solution is buffered using sodium bicarbonate and in theory this should help break down excess sodium sulfide for those of you who are interested in knowing more details I've included a small write-up moving on I went ahead and prepared another sodium sulfide solution and then I dumped it in just like before I let it sit for about an hour and then I ran another test this time it came up negative so I knew that I had added enough sodium sulfide the next step is to filter off the mercury sulfide but if I do it right now it's going to be a huge pain my recommendation is to let it stand for something around 24 hours and to let the mercury sulfide settle at the bottom not everything will settle out but with the majority of it at the bottom the filter is not going to get blocked nearly as often later the next day I set up a makeshift filter I drilled a bunch of holes in the bottom of a plastic container and then I dropped in a filter paper on top of the filter paper I then dumped in a whole bunch of sea light it's basically just very fine silicon dioxide and it's actually very important to use here it's used to trap very small particles of mercury sulfide that would normally just pass right through a filter paper on top of this it also helps prevent the filter paper from clogging up once I was ready to filter things I started out by adding a little bit of water on top of this I pour in the suspension of mercury sulfide as I pour it you can see that some of the sea light is being pushed to the side because of this the filtering in that spot isn't as good and some mercury sulphide is able to pass through this stops happening very quickly as the see light sinks back to the bottom but whatever we collect in the first minute or so has to be refill turd as the solution filters through I occasionally top it off that I'm collecting is nice and clear and it appears to be free of mercury sulphide it's very important that you examine it closely and make sure that there's no mercury sulfide floating around if any mercury is making it through the filter needs to be fixed and everything needs to be passed through it again it was occasionally necessary to empty the container all of the waste was transferred to a large water container and I'll show you how I deal with that later in the video as the filtration continued a lot of mercury sulphide collected at the bottom of the filter and the filtration slowed down it eventually stopped so I needed to clean out the filter it's kind of a pain but it honestly wasn't too hard to do the water in the filter was transferred to another container and using a plastic spoon I scooped out the mercury sulphide with most of the mercury sulphide removed I continued with the filtration in the beaker on the left here I have the stuff that I scooped out using the spoon when I mostly just had sediment left in the five liter beaker I transferred it to the smaller one you see on the right I want it to liberate the large beaker because while this is filtering I can process the rest of the mercury waste whatever remained from the first container was transferred to the beaker the container was washed several times with water to make sure that no mercury remained the solid stuff that was filtered off was washed with a little bit of water and transferred to a ziploc bag I transferred the waste from the other large bottle and like before I couldn't add all of it so unfortunately I did have to repeat the process for a third time anyway what I do here and what I do in the third run is the exact same thing as before and I don't want to bore you guys so I'm just going to jump ahead after processing all of the mercury waste this is the mercury sulphide that I've collected the stuff on the left is relatively clean but the stuff on the right is filled with sea light and actually has filter papers mixed in as you saw earlier the filter tended to get clogged and every so often I had to scoop out the mercury sulphide I did my best not to remove any sea light and the stuff I scooped out here was transferred to the beaker on the left at some point though even when I did this it still stayed clogged so I needed to remake the filter everything knows in there including the filter paper was scooped out and transferred to the beaker on the right when the filtration was done I had to do this again so the stuff on the right contains two filter papers and a whole bunch of sea light what I need to do now is a vacuum filtration to pull away any water that remains a filter paper was added to the buter funnel along with a whole bunch of sea light it wasn't as pure as I thought it was and there was a bunch of sea light at the bottom I decided not to include it in this filtration and I'll filter it off with the dirty stuff I turned on the vacuum but the filtration is pretty slow I let it run for several minutes and when I came back it seemed reasonably dry to clean it up a little bit more I washed it a few times with warm water after the third washing I left the vacuum on for several minutes to get it as dry as possible I then used a plastic spoon to carefully scoop it out of the filter I tried my best not to scoop out any sea light but I ended up getting a little bit I transferred as much as I could to a piece of paper and then I moved on to filtering the crappy stuff everything was transferred to the filter and I washed the beaker a few times with water like before I then kept the vacuum on for a few minutes to dry it up as much as possible once it was dry the entire contents of the funnel was transferred to a piece of paper so here's the final mercury sulphide products on the Left I have the relatively clean stuff and on the right I have some clearly dirty stuff it looks like there's way more crappy stuff but it's a little bit deceiving because most of it is just paper and sea light I ended up using all of the sea light that I had and from a previous shot you can see it was quite a bit the crappy stuff was transferred to a container and I labeled it as mercury sulfide waste the cleaner mercury sulfide was placed over some paper towels and I let it dry for a few days using a paper towel and some water I then wiped down the workspace all of the paper towels that I used here were transferred to the mercury waste ziploc bag at this point I'm unfortunately not done yet and I still have some waste to process all of the water that filtered through was transferred to this water jug as the sodium sulphide slowly broke down the solution took on this yellow color in any case it still reeks of sulfur and I'm going to have to detoxify it luckily for me there's a pretty easy way to clean it and I just need some chlorine tablets before proceeding on it's highly recommended to test the solution and make sure that there's no mercury sulfide dissolved in it to do this I put some bleach into a beaker and I drop-wise added the sulphide solution once it's added a white precipitate appears and this is perfectly normal we just have to make sure that nothing Brown appears the brown stuff would be mercury sulfide and if it showed up here I pretty much have to redo everything I pour a bunch of the tablets into a beaker and then I transfer it to the water I start by adding in just one tablet to gauge the reaction and make sure things don't bubble over when nothing much happened I went ahead and added the rest once everything is added we basically just let it sit here and wait for everything to react in water especially under dilute conditions sodium sulfide pretty quickly breaks down so what I'm dealing with here should be mostly just sodium bisulfite the pool tablets that I'm using are made of calcium hypochlorite and they should react with all of the sulfide they should lead to the formation of sulfate salts which don't smell and are relatively inert I let it sit for a few hours and when I came back it looked like a lot of gun on but only in the lower portion to get everything to react I had to use a stick to mix things up also to speed things up I added a second beaker of the pool tablets you need to be careful here because I'm generating co2 gas and if I mix things too thoroughly I could have it bubble over after a few hours it stopped smelling like sulfides and I was more or less done I stopped mixing things and I let the solid stuff settle at the bottom the calcium hypochlorite tablets are not very pure and a good portion of the stuff at the bottom is just insoluble stuff from the tablets I let the water here sit for about a day just to make sure that all of the sulfide has been destroyed the blue color of the bottle makes it look green but it's actually closer to yellow this yellow color is normal and it's because we have calcium hypochlorite dissolved in the solution the waste that I have here is now relatively inert and to get rid of it I pour it down the drain before pouring anything down the drain though it's really important to make sure that you're not destroying the environment what I have here is just dilute bleach mix with a bunch of inert salts there might be some trace mercury still left over but the amount is probably almost undetectable a few days later I come back to the mercury sulfide and it's relatively dry it was transferred to a chemical bottle and Wade and I got a mass of about 59 grams in the end after the entire cleaning process this is what I have on the Left I have the clean mercury sulphide in the middle is all the dirty stuff and on the right is just miscellaneous contaminated things anything that was contaminated with mercury sulfide or any other form of mercury was transferred to this bag at some point I'm going to need to dispose of the contaminated things by either giving it to my city or paying a company to take it away to deal with the dirty mercury sulfide I'm going to be recycling it back to metallic mercury that video should be posted within the next month or so in terms of the cleanup it's pretty easy to get rid of the mercury sulfide by just wiping it with a wet paper towel I thoroughly wipe down everything that the mercury sulphide came into contact with and the paper towels were added to the ziplock bag anyway that's all I really have to say about this stuff let me know what you guys think about this whole waste recycling series and let me know what other things you'd like to see me deal with also I finally received my Nile red beakers and I've opened up a shop online the website is just Nile red dot CA and if any of you are interested in checking it out there's a link in the description right now the site only accepts orders from Canada or the US so if you're from somewhere else and you want to get something just send me an email at this address here so as usual I'd like to thank everyone who's supporting me on patreon everyone who supports me will see my videos 24 hours before I release them to YouTube on top of this all of my supporters can directly message me on patreon with any questions or comments that they have and I do my best to respond within about a day or so to all of my patreon messages also if you support me with $5 or more you'll get your name at the end of the video like you see here here's just a small list of some of the future videos that I'll post if you guys have any other ideas please let me know in the comments

Channel: NileRed

Views: 1,417,427

Rating: 4.9347835 out of 5

Keywords: nile, red, recycle, waste, chemical, mercury, cinnabar, sulfide, purify, sodium, bicarbonate, neutralize, metal, nilered, chemistry, science

Id: S4T57SFntIs

Length: 20min 31sec (1231 seconds)

Published: Mon Feb 13 2017