Fig. 4From: Chitosan impregnation of coconut husk biochar pellets improves their nutrient removal from eutrophic surface waterBiochar at 20 g L−1 in DI water (a) CH, (b) CHC, and (c) CHEG, released different amounts of anions and cations after 2–48 h shaking at 120 rpm and temperature of 30 °CBack to article page