fig1

Figure 1. Response surfaces and contours of iodine adsorption by ZSC under three single factors. (A) Three-dimensional response surfaces and (B) contour plots of pyrolysis temperature (700-900 °C) vs. pyrolysis time (1.0-2.0 h); (C) Three-dimensional response surfaces and (D) contour plots of pyrolysis temperature (700-900 °C) vs. mass ratio of ZnCl₂ to sludge (1:2-2:1); (E) Three-dimensional response surfaces and (F) contour plots of pyrolysis time (1.0-2.0 h) vs. mass ratio of ZnCl₂ to sludge (1:2-2:1). ZSC: ZnCl₂ modified sludge biochar.