TiO2 nanoparticle sorption to sand in the presence of natural organic matter

Evaluation of Strength Properties of Sand Modified with Organic Polymers

“…Five concentrations (10%, 20%, 30%, 40%, and 50%) of polymer dilutions were proposed for sand reinforcement, with water (0%) as a control. The three dry densities of the prepared samples were 1.40, 1.50, and 1.60 g/cm 3 , respectively. The additive amount of polymer dilutions was 10% by weight of dry sand.…”

“…The specimen with density 1.40 g/cm 3 had loose structure, the one with density 1.50 g/cm 3 fell down immediately after stripping the mould and had a partly broken structure, and the other one with density 1.60 g/cm 3 had a rupture at the bottom and could keep the specimen standing. However, while the unreinforced specimens with density 1.60 g/cm 3 were moved gently, they got damaged immediately. Therefore, the unconfined compression test could not be carried out for the unreinforced specimens.…”

“…Its particle size distribution is shown in Figure 1. It has a specific gravity (Gs) of 2.64, maximum dry density (ρmax) of 1.66 g/cm 3 , minimum dry density (ρmin) of 1.34 g/cm 3 , maximum void ratio (emax) of 0.97, minimum void ratio (emin) of 0.59. Its particles have a mean grain size (D50) of 0.30 mm, gradation coefficient (Cg) of 1.13, and uniformity coefficient (Cu) of 2.77.…”

“…Firstly, the weight ratio (5:5:2:17) of poly-oxypropylene diol (PPG, Jining Hongming Chemical Reagent Co., Ltd., Jining, China) with molecular weight 2000, poly-oxyethylene glycol (PEG, Shanghai Ika Biotechnology Co., Ltd., Shanghai, China) with molecular weight 2000, poly-caprolaclone glycol (PCL, Jining Hongming Chemical Reagent Co., Ltd., Jining, China) with molecular weight 1000, and toluene were mixed with the conditions of temperature 145 • C and air distillation. After most of the toluene was dried, with stirring for 1 h. After that, lauryl sodium sulphate (Qidong Mingcheng Chemical Co., Ltd., Nantong, China) was mixed according to the definite weight percentage of polyurethane prepolymer to obtain the final organic polymer, a light-yellow liquid with a pH of about 7, specific gravity of 1.15 g/cm 3 , viscosity of 650-800 mPa·s, solid content of 88%, coagulation time of 60-1600 s. The organic polymer solution in this study was prepared with distilled water. The mixture of liquid polymer ( Figure 2a) and distilled water were stirred for about 10 min to obtain the desired solution (Figure 2b).…”

“…Chemical reinforcement for soil improvement is a popular method using additives such as traditional stabilizers and non-traditional additives. The traditional chemical stabilizers such as lime, fly ash, zeolite gypsum, cement, and other industrial wastes have more advantages for the improvement of soil strength [1][2][3][4], but most of the traditional additives easily increase the pH value of soil, resulting in the environmental problems of polluting ground water or obstructing vegetation growth [5,6]. Recently, non-traditional chemical additives such as liquid polymers, enzymes, ions, and lignin derivatives have been studied [7][8][9].…”