Biochar is, in my opinion one of the most interesting, emerging technologies for ion exchange as it applies to water. While the carbon function of this material holds interest, it is the ion exchange capability that hold my attention, and frankly hints are new possibilities for cleanly and efficiently removing inorganic material from our water supplies.
For those who don’t know what ion-exchange is, the most clear teaching example of it is the home water softener. The “beads” inside the softener are charged with sodium. In the presence of hard water, calcium, the bead favors and holds calcium and gives off sodium, thereby creating soft water. Once exhausted, the beads are soaked with very concentrated sodium (salt), and readily give up the calcium to drain, recharging the bead with sodium, making it ready to treat more hard water.
I am proud to say that I am the only scientist to ever accomplish this regeneration on a biochar material. I accomplished this at Glanris and received a patent for it.
Up until now the ion exchange capacity of biochar has only been cation functional, meaning the media can hold metals such as calcium, iron, lead and other so-called metals. With that, I am also proud to say that my partner and I have succeeded in converting the cationic functional groups to anionic functional groups. This has exciting water purification potential with contaminants like Fluoride, and even PFAS. A lot more farting around (R&D) has to be done, but we are fixing to do exactly that.
An exciting part of biochar ion exchange is that the raw material required for manufacturing is not only in abundance, but it is dirt cheap, and also inexpensive to process.
Some point to a low capacity per pound as a draw back to biochar, but these are individuals who do not understand ion-exchange. Every mechanical and chemical process is defined by the mass balance and energy balance. In simple terms it is the proper scientific examination of resources in versus resources out. Let’s look at a simplified example to illustrate. For argument’s sake, imagine that I am considering two different ion exchange media for my process.
Media #1: 100 regeneration units per pound
Media #2: 10 regeneration units per pound.
Why would I choose Media #2 over Media #1? How can this be the right choice? Well, as we compared, we learned a few things:
- Media #1 only provides one gallon per minute per pound. Media #2 provides 20 gallons per minute per pound. The takeaway? A system to use Media #1 has to be 20 times larger.
- It costs $100 per pound to regenerate Media #1. It only costs $2 per pound to regenerate Media #2
Now you can do the arithmetic for yourself, but the point is, the only real comparison of two ion exchange media is, you guessed it, cost per unit of contaminant removed.
In the case of our new findings, we can regenerate the anion form of a biochar using a very common waste product found in many manufacturing plants. Stay Tuned for more!