Lignocellulose-Based Superabsorbent Polymer Gel Crosslinked with Magnesium Aluminum Silicate for Highly Removal of Zn (II) from Aqueous Solution

Lignocellulose (LCE) was ultrasonically treated and intercalated into magnesium aluminum silicate (MOT) clay to prepare a nano-lignocellulose magnesium aluminum silicate polymer gel (nano-LCE-MOT) for the removal of Zn (II) from aqueous solution. The product was characterised using nitrogen adsorption/desorption isotherm measurements, Fourier-transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The conditions for the adsorption of Zn (II) on nano-LCE-MOT were screened, and adsorption kinetics and isotherm model analysis were carried out to explore the adsorption mechanism and achieve the optimal adsorption of Zn (II). Optimal adsorption was achieved at an initial Zn (II) concentration of 800 mg/L at 60 °C in 160 min at a pH of 4.52. The adsorption kinetics were explored using a pseudo-second-order model, with the isotherm adsorption equilibrium found to conform to the Langmuir model. The maximum adsorption capacity of the nano-LCE-MOT polymer gel toward Zn (II) is 513.48 mg/g. The materials with adsorbed Zn (II) were desorbed using different media, with HCl found to be the most ideal medium to desorb Zn (II). The optimal desorption of Zn (II) was achieved in 0.08 mol/L HCl solution at 65 °C in 60 min. Under these conditions, Zn (II) was almost completely desorbed from the adsorbents, with the adsorption effect after cycling being slightly different from that of the initial adsorption.

Reaction products of Sm2Zr2O7 with calcium-magnesium-aluminum-silicate (CMAS) and their evolution

During flight, many silicates (sand, dust, debris, fly ash, etc.) are ingested by an engine. They melt at high operating temperatures on the surface of thermal barrier coatings (TBCs) to form calcium-magnesium-aluminum-silicate (CMAS) amorphous settling. CMAS corrodes TBCs and causes many problems, such as composition segregation, degradation, cracking, and disbanding. As a new generation of TBC candidate materials, rare-earth zirconates (such as Sm2Zr2O7) have good CMAS resistance properties. The reaction products of Sm2Zr2O7 and CMAS and their subsequent changes were studied by the reaction of Sm2Zr2O7 and excess CMAS at 1350 °C. After 1 h of reaction, Sm2Zr2O7 powders were not completely corroded. The reaction products were Sm-apatite and c-ZrO2 solid solution. After 4 h of reaction, all Sm2Zr2O7 powders were completely corroded. After 24 h of reaction, Sm-apatite disappeared, and the c-ZrO2 solid solution remained.

Reaction products of Sm2Zr2O7 with calcium-magnesium- aluminum-silicate (CMAS) and their evolution

During flight, many silicates (sand, dust, debris, fly ash, etc.) are ingested by an engine. They melt at high operating temperatures on the surface of Thermal barrier coatings (TBCs) to form calcium-magnesium-aluminum-silicate (CMAS) amorphous settling. CMAS erodes TBCs and causes many problems, such as composition segregation, degradation, cracking, and disbanding. As a new generation of TBC candidate materials, rare-earth zirconates (Sm2Zr2O7) have good CMAS resistance properties. The reaction products of Sm2Zr2O7 and CMAS and their subsequent changes were studied by the reaction of Sm2Zr2O7 and excess CMAS at 1350°C. After 1 h of reaction, Sm2Zr2O7 powders were not completely eroded. The reaction products were Sm-apatite and c-ZrO2 solutions. After 4 h of reaction, all Sm2Zr2O7 powders were completely eroded. After 24 h of reaction, Sm-apatite disappeared, and the c-ZrO2 solution remained.