Oxalic acid dihydrate

A thirty-six percent total solid content of low-ammonia NRL was obtained from the Chinese Academy of Tropical Agricultural Sciences (Danzhou, China). Sepiolite concentrate (X-ray fluorescence (XRF) chemical analysis indicated that the composition of this fraction is 65.19% SiO₂, 20.25% MgO, 7.89% Al₂O₃, 3.11% Fe₂O₃, 1.05% CaO) was obtained from Qingdao Zhongxiang Environmental Protection Technology Co., Ltd (Qingdao, China). The silanes, namely Triethoxyvinylsilane (VTES; 97%; M_w = 190.31 g/mol), (3-Mercaptopropyl)Triethoxysilane (MPTES; 98%; M_w = 238.42 g/mol), and Bis[3-(Triethoxysilyl)Propyl]Tetrasulfide (TESPT; 90%; M_w = 538.95 g/mol), were purchased from Shanghai Macklin Biochemical Technology Co., Ltd. (Shanghai, China). Oxalic acid dihydrate (OA, C₂H₂O₄·2H₂O, AR), zinc oxide (ZnO), and stearic acid (SA) were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). The N-cyclohexyl benzothiazole-2-sulphonamide (Accelerator CZ), 2,2′-dibenzothiazoledisulfde (Accelerator DM), and sulfur (S) were industrial grade and provided by SanLux Co., Ltd. (Shaoxing, China).

The LiV₃O₈ sample was prepared by a sol-gel method. In a typical synthesis, 0.702 g NH₄VO₃ (99% A.R., Sinopharm Chemical Reagent Co., Ltd., Beijing, China) and 1.008 g oxalic acid dihydrate (99.9% A.R., Sinopharm Chemical Reagent Co., Ltd., Beijing, China) were added into 36 mL deionized water at 70 °C and stirred for 30 min. Then, 0.084 g LiOH (99.9% A.R., Sinopharm Chemical Reagent Co., Ltd., Beijing, China) was added into the solution, and it was stirred at 70 °C for 90 min to obtain a homogenous solution. Then, the mixture was stirred at around 80 °C to dry. The obtained precursor was well ground and calcined at 400 °C for 2 h in an air atmosphere with a heating rate of 5 °C min⁻¹. The final product was obtained after cooling down to room temperature.

N,N-Dimethylformamide (AR, ≥99.5%), oxalic acid dihydrate (AR, ≥99.5%), and methylene blue (≥98.0%) were purchased from Sinopharm Chemical Reagent Co. Tetrabutyl titanate (TBOT, ≥99.0%) and sodium hydroxide (≥98%) were purchased from Aladdin Biochemical Technology Co. Absolute ethanol (AR, ≥99.7%) was purchased from Beijing Innochem. Science & Technology Co. All reagents and solvents were used without further purification.