Mitigating evaporation and desiccation cracks in soil with the sustainable material biochar

J of Applied Polymer Sci

Qiu

Liu

et al. 2021

In this study, the application of superabsorbent resin (SAP) in inhibiting the soil moisture evaporation (or slowing down the water outflow) was studied. The clay‐SAP composites were fabricated by grafting of poly (acrylic acid‐N‐hydroxymethyl acrylamide/clay) (GT‐g‐P [AA‐co‐NHA]/clay) on Tragacanth gum (GT), using solution polymerization. The structure, morphology and stability of the clay‐SAP composites were investigated by Fourier transform infrared, scanning electron microscope and TGA. The maximum swelling ratio of Attapulgite (3%)‐, Kaolin (3%)‐ and Montmorillonite (3%)‐SAP composite in deionized water reached 1180, 819 and 525 g/g respectively, and the maximum swelling ratio in tap water reached up to 206, 192 and 170 g/g respectively. Meanwhile, the maximum swelling ratio in 0.9% NaCl solution was 95, 82 and 62 g/g respectively. The water retention of clay‐SAP composites was also analyzed as a function of temperature. In addition, by simulating the desertification area, the effect of the APT (3%)‐SAP composite on the anti‐evaporation performance was studied. The obtained results revealed that the water retention of APT (3%)‐SAP composite was 36% at 45°C for 12 h. Under natural conditions, the evaporation rate of the anti‐evaporation material was inversely proportional to the amount of APT (3%)‐SAP composite added.

Section: Introductionmentioning

confidence: 99%

Preparation and anti‐evaporation properties of organic–inorganic superabsorbent based on Tragacanth gum and clay

J of Applied Polymer Sci

Qiu

Liu

et al. 2021

“…and studied the development of surface cracks on soil with biomass ash by using image processing technology and the fractal theory. Some scholars found that the addition of biomass ash to soil can effectively prevent the evaporation of water in the soil and soil cracking [12,13]. Wang et al (2021) and Bing et al (2021) proposed a statistical framework to describe the probability of the distribution of the fractured area as a function of the water content.…”

Section: Introductionmentioning

confidence: 99%

Effect of Salt Content on the Evaporation and Cracking of Soil from Heritage Structures

Cui

Advances in Materials Science and Engineering

et al. 2021

The degree of damage to heritage structures in arid areas can be particularly serious due to long-term exposure to a harsh arid climate. In this paper, the characteristics of evaporation and cracking of soil taken from heritage structures with different NaCl concentrations are experimentally investigated by subjecting saturated soil samples taken from the Wang-Jing tower in Weihui City, Henan Province. Making soil sample of water content of 110% is used to test the rate of evaporation at a constant temperature and humidity, through which the changes in the evaporation rate, water content, fracture development, and fracture fractal dimension are obtained. The results show that, (1) with higher water content, NaCl can affect the evaporation process by increasing the matrix suction of the soil of the Wang-Jing tower and then affect the cracking process of soil. When 0%, 1%, 2%, and 4% NaCl are added, the residual water content of the samples is 3.15%, 4.23%, 4.82%, and 5.89%, respectively, which show an obvious trend of increasing water content; (2) the period with a stable fracture fractal dimension of the samples is shortened with an increase in NaCl concentration, and its maximum fractal dimension is reduced in turn; and (3) at a lower water content, NaCl crystallizes and precipitates in the pores of the soil, which provide a cementitious effect among the soil particles, thus inhibiting crack development.

“…However, contaminated soil used in this study, which was obtained from a mining field in Zhuzhou, Hunan, had a very high concentration of lead (12510 mg/kg) and zinc (11927 mg/kg), while limited research has been conducted on the effectiveness of biochar when applied into contaminated soil with that high concentration pollution. e biochar can effectively change the porosity and the pore distribution in soil, which can improve the pore structure of soil and the circulation of the water and air in the pores [11,12]. Also, some researchers focus on the engineering application of remedied soil [13,14].…”

Section: Introductionmentioning

confidence: 99%

Application of Biochar in the Remediation of Contaminated Soil with High Concentration of Lead and Zinc

Advances in Civil Engineering

Yang

et al. 2021

Self Cite

Soil contamination in the Panjiachong lead and zinc mining areas has become a severe problem in Hunan Province, China. As the traditional stabilization technology comes with soil degradation, it is urgent to find a novel binder that is more eco-friendly. It has been proved that biochar can immobilize heavy metals, but limited research has been conducted on the contaminated soil with high concentration. In this study, 5%, 8%, and 10% biochar derived from the rice straw were used to remediate contaminated soil with high concentration of lead and zinc. Portland cement (PC) was adopted as the control group. The results showed that after 56 d curing, the biochar-treated soil had a neutral pH and EC value and higher soil fertility compared with the PC-treated soil. The results from the toxicity characteristic leaching procedure test indicated that the biochar is more effective than PC on heavy metal immobilization. Germination index (GI) value was used to evaluate the phytotoxicity of the treated soil; the GI values of treated soil with 8% and 10% biochar were both higher than 80%, while all the PC-treated groups failed to achieve this GI value, which indicated the potential revegetation is applicable for the biochar-treated soil.