I won't deny the fact that having couple of dried charcoal in a sealed container prevents fungus but may not be ideal as it is dusty. There are bamboo carbon air freshener but I am not sure how effective.
Yes, dry charcoal does absorb moisture and the large surface area of fine pores traps smells and dirt as well. Good for water and air filtration in removing dirt, smell, color and large molecular chemical. And carbon does in certain extend inhibits mold and bacteria growth. Primary used for non sensitive item like apparels. There are activated carbon without the carbon dust but only used for filtration and not BBQ charcoal.
Activates carbon pills are used to stop diarrhoea and slows food poisoning effect by absorbing the toxin in the stomach.
Charcoal for fridge must be placed where in the path of air flow. Is BBQ charcoal more effective than thirsty hippo, depends on the moisture level.
Charcoal absorbs at slower rate, thus does not exhaust fast in very high humidity environment. Calcum chloride hippo does not do well in very high humidity bec the calcium chips dampen too fast, disintegrate and drop into the solution. Once in solution they dissolve an becomes ineffective.
Which the reason you notice that in a low damp cabinet, the water level in the container can reach very high, while some only 50%. Worst are the cheap brand where the most would have dropped to the bottom before starting.
she helped me gather charcoal, those used for bbq and kept them in an airy bag. using that as moisture sucker. she says it works wonder and last much much longer than thirsty hippo which eventually turns into liquid. i wonder if anyone uses this method as well. im a newbie. but it seems that the curboard really feels dry inside. the size of the cabinet is about say, 1 and a half A3 size paper?