Fig. 4From: Eco-friendly cellulose-based hydrogels derived from wastepapers as a controlled-release fertilizerMaximum swelling percentage of cellulose hydrogels consisted of different % (w/v) of (a) cellulose fibers and (b) CMC. Different letters indicate significant differences (p ≤ 0.05) between hydrogels. Error bars show the standard deviations from triplicates (n = 3)Back to article page