Dear Nath

Generally biochar is negatively charged, However, ever you can modify it to enhance the heavy metal sorption.

The articles given below explain the main mechanisms governing the sorption of heavy metals.

Article Mechanisms of metal sorption by biochars: Biochar characteri...

Article A Review of Biochar as a Low-Cost Adsorbent for Aqueous Heav...

Piyal aravinna

https://www.sciencedirect.com/science/article/pii/S138589471930350X

This review article will answer your questions the best.

Thank you Mr. Zheng. I have followed many of your research papers and it is really helpful.

Dear Mr. Nath

Briefly, the influence of activation depends on a variety of parameters. For instance; The raw material of adsorbent, the method of activation, the temperature/kind of chemical activator, the time of activation, to name but a few.

You can take a look on a lot of paper, review-paper, and chapters which have been published in recent years, and compare the effects of different parameters on the improvement of adsorbent after activation. Though in general, mostly activation has a tremendous effect on the surface-to-volume ratio of adsorption; therefore will have a great effect on adsorption efficiency.

Cheers.

Hamid

Dear researcher,

As you may know the difference between activated carbon and carbon itself is that activated carbon is a porous material and has pores in comparison with carbon structure. There are different pores in size in activated carbon structure including mesopores and micropores. By using activated carbon for absorbing materials you may have better absorbance because of the pores in the structure.

Hi

Various modification methods have been developed in recent years to further enhance the sorption ability of biochar. Research has suggested that chemical modification could increase the number of functional groups, BET and surface porosity on the surfaces of biochar and enhance metals adsorption capacity.