Citric acid monohydrate

Commercial xanthan gum, with a purity > 91% and molecular weight (M_w)~1.0 × 10⁶ g/mol, was purchased from Galeno srl (Prato, Italy) in the form of fine powder and used as received. Natural cellulose fibers (Arbocel grade R) were kindly provided by J. Rettenmaier & Söhne Gmbh (Rosenberg, Germany) in the form of powder with an average fiber length of 200–300 µm and bulk density of 60–105 g/L [66 ]. Citric acid monohydrate, with a purity 99.5–101% and M_w~210.14 g/mol, was supplied by Riedel-de Haën GmbH (Seelze, Germany) and used as a crosslinking agent.
The soil was sampled from a forest near the city of Trento (Italy). Appropriate analyses for the characterization were carried out by Fondazione Edmund Mach (San Michele all’Adige, TN, Italy), and its main properties are reported in Table 1. As a benchmark, tests on the soil were also performed using a commercial potassium polyacrylate-based soil conditioner, called Idrogea and purchased from Endofruit srl (Verona, Italy). According to the technical datasheet, the concentration of this product to be used in the soil is 0.13 wt%.

Bleached bagasse Kraft Pulp was kindly delivered by Qena Paper Industry Company, Egypt. The chemical composition of bagasse pulp was 71% α-cellulose, 30% pentosans, 0.8% ash, and a degree of polymerization (DP) of 1200. Risedronate sodium was kindly supplied by Hikma Pharmaceutical and Chemical Industries Company, Egypt. Chitosan low molecular weight, NaOH, urea, NaBr, NaClO, 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) were purchased from Sigma-Aldrich, Germany. Citric acid monohydrate was purchased from Riedel-deHaen, Germany. Fetal bovine serum (FBS), L-glutamine, penicillin G sodium, streptomycin sulfate, and amphotericin B were obtained from Lonza, Basel, Switzerland. MTT (3-[4, 5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide), acridine orange and ethidium bromide were obtained from Merck, Darmstadt, Germany.