Hey Folks!
SO: This may be a good time for me to introduce something that I have been meaning to do for a while....
Reclaiming SolventI had planned to do a pictorial guide to cleaning and reusing the NPS that we use for DMT extractions. SO, with that in mind, I'll do it when I get back to my house this evening. In fact, I am preparing for a relocation and I have a hidden stash of "old NPS" that needs to be cleaned and replaced in the appropriate containers before it can be transported or disposed.
Bear with me, I'll probably not be able to get the full write up finished until Thursday or Friday. For now, if you have some solvent - just store it for a few days, and I'll try to get the complete guide composed ASAP. We've got a lot going on, but this needs to be addressed before I relocate. (I'll include the procedure, step by step, with a picture to accompany each step.)
Th Entity has brought up a valid point - what about the base mix? That was a concern of mine as well. I sought after a method to "neutralize" and dispose of the material with minimal hazards to the environment. So, I wondered: What is the best approach for an individual that does not have access to a formal lab?
(In a formal lab setting, we collect all waste, label it, store in a specific location designated for wastes, keep the halogenated solvents separate from the other organic solvents, oxidizers separate, flammables separate, etc etc etc.) IMO, this is the best approach for organic solvents (NPS), though it is not practical for someone who isn't within a laboratory network.
Another option: You can clean the solvent via the method that I will propose in the next few days, return it to the original container, and take it to a waste facility. They generally have a designated location for things like motor oils and other products that could be hazardous to the environment. You can simply say, "This is used naphtha (or other solvent) that I didn't want to throw in the trash." If they do not have a means of handling organic solvents, then they should be able to direct you to a proper disposal facility. It may help to call the facility, ahead of time, and ask if they accept 'waste oils or used cleaning solvents.'SO, there still lies the question about the base mix. That can be safely neutralized - but, I would not recommend attempting to do so without the proper safety equipment. Unfortunately, it will be rather difficult to completely separate ALL of the organic solvent from the aqueous - they are miscible to an extent. We can consider a few options:
First, the neutralization procedure. IMO almost every tek suggests large amounts of a strong base. Ok, fine - while that will work, I've found that the excessive amounts of base are not needed. I wanted to experiment with natural acidification using the tannins found in bark, and then determine the estimated quantity of sodium hydroxide that is needed to achieve and maintain a stable pH of >13. If you'd like, you can see the report
here.Essentially, I found that I'd been using WAY too much sodium hydroxide in my previous extractions. With the method I presented, it required roughly 1/5th of the mass that is commonly recommended. Make of that what you will - it's personal preference; I am trying to be more conservative about the resources I use during an extraction process.
Sodium hydroxide is a strong base - it totally dissociates in water. This is good! This means we can use a strong acid, like HCl, to neutralize the mix.
NaOH + HCl -> H2O + NaCl
The reaction between HCl and NaOH yields water and table salt! This is good news, because the products are non-hazardous to the environment. HOWEVER!!!!! Neutralizing, by using a strong acid and a strong base, is highly exothermic. If the acid and base are mixed at a fast rate, you'll likely have a very dangerous mess to clean; or potentially injure yourself. Again: safety, safety, safety!!! I cannot emphasize that enough. With the proper safety equipment, this can be done - but, not quickly - and, not recommended for conditions with an excess of either.
You would need a molar equivalency (1:1) of the acid and the base. With the high levels of NaOH used, it will likely require a decent amount of acid (relative to the scaling.)
Let's assume that the neutralization process went well, and now you have a neutral mix of bark, water, salt and ..... that trace naphtha (or other solvent.) So, there is the kikker, right? No matter what, there is going to be some of the organic solvent that will remain trapped in the mix. From here, there are a few options - but, I recommend looping back around to: placing the neutralized mix in a safe container, and delivering it to the local waste facility. You could say, "We used this water to clean some paint brushes after a project, and we're concerned that there is some paint thinner remaining in the water. It's got some soil and debris in there, too - I accidentally dumped the soil from a plant (that was being re-potted) into the wrong bucket. Where should it be disposed?" If you don't feel comfortable with that: Understandable. I think it is the most environmentally safe option.
Burning the solvent: or allowing the solvent to evaporate, will release green-house gasses into the atmosphere. Is it being done? Yes. The combustion of hydrocarbons results in: (The choice of pentane is arbitrary. I got tired of typing CHx-, so I stopped at 5.)
Pentane + Oxygen (gas) -> Carbon dioxide (gas) + water
CH3-CH2-CH2-CH2-CH3 + 16 O2 -> 5 CO2 + 6 H2O
So, either way: evaporation or combustion will result in the increased concentration of greenhouse gasses. LOL... funny world, eh?
Anyways, with this wall of text, I hope that it can offer some considerations while we move towards environmentally friendly procedures.
Personally? I clean and reuse solvent. I don't evaporate the solvent, or burn it, or dump it. That costs money!! LOL. The cleaning procedure is REALLY cheap, and REALLY easy. In my current region, the big box stores are no longer selling naphtha.
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So, I have to reclaim the solvent if I wish to continue using it.
I neutralize the bark mix, and dispose of the material at the local waste facility. I have not had any trouble from the folks there, they don't care what you were doing with it. They are just waiting for 5 o'clock to come and then they can go home. They see painters, contractors, landscapers, and etc. who all bring used chemicals to the facility on a daily basis.
I hope that can clarify some of the options for waste disposal.
If you have any questions, feel free to ask!
Take Care,
ACY
Sometimes it's good for a change. Other times it isn't.