Graphite, BN, MoS₂ and WS₂ are readily exfoliated using probe sonication in the presence of p-(trimethylammonium)methyl-calix[8]arene resulting in few-layer laminar material. The positively charged material is effective in the removal of nitrate ions from waste effluent, as is the negatively charged corresponding material stablized by partially deprotonated p-phosphonic acid calix[8]arene, with scope for efficient recycling.