Utilization of nano-olive stones in environmental remediation of methylene blue from water

Abstract

Background The use of agricultural waste as a low-cost adsorbent for the removal of hazardous methylene blue (MB) from aqueous solution was investigated. In this research, the potentiality of using black nano olive stones (black NOS) and green nano olive stones (green NOS) for MB adsorption was conducted. Methods Various remediation parameters such as initial MB concentration, pH, and temperature were investigated. Thermodynamic study was carried out to determine the homogeneity of the adsorbent and spontaneity of the adsorption process. Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius and pore volume. Results It was found that NOS exhibits an acidic nature, however the highest MB removal efficiency was recorded at pH 10; reaching up to 71%. The negative value of the heat of the adsorption process (ΔH°) indicated the reaction followed an exothermic pathway while the negative value of Gibbs adsorption (ΔG°) further suggested its spontaneous nature. The results indicated that the Freundlich model described well the adsorption process with 99.5% correlation coefficient for green NOS. FTIR was used to analyze functional groups on the adsorbents' surfaces that could play vital roles in the remediation process. SEM analysis revealed that the adsorbents comprised of abundant spherical deep cavities and porous nature. Conclusion The result obtained successfully demonstrated the potential of using black and green NOS as suitable adsorbents for the removal of MB from water.

Preparation of Magnetic Surface Ion-Imprinted Polymer Based on Functionalized Fe3O4 for Fast and Selective Adsorption of Cobalt Ions from Water

“…The N 2 adsorption capacity of Fe 3 O 4 @SiO 2 @MPS and Co(II)-MIIP increased slowly in the low pressure region (P/P 0 < 0.5), and sharply increased in the high pressure region (0.8 < P/P 0 < 1.0), indicating that the N 2 isotherm of two materials belonged to category IV isotherm. There were abundant mesoporous structures on the surface of the materials [32]. In addition, it could be found from the figure that the N 2 adsorption capacity of Fe 3 O 4 @SiO 2 @MPS was significantly greater than that of Co(II)-MIIP.…”

Neodymium recovery from NdFeB magnets: a sustainable, instantaneous, and cost-effective method

“…Similarly, features at 1417 cm −1 , 1121 cm −1 , 992 cm −1 , and 1626 cm −1 correspond to -CH 2 bending, C-OH stretching, -CH 2 -O-CH 2 stretching ( pyranose ring), and -COO vibration (-COO − Na + ), respectively. 38,40 After adsorption of Nd 3+ , the peaks due to -OH stretching, -CH 2 bending, C-OH stretching, -CH 2 -O-CH 2 stretching were shifted to 3323 cm −1 , 1421 cm −1 , 1111 cm −1 , and 1001 cm −1 , respectively. Interestingly, we have observed the -COO peak which was previously present at 1626 cm −1 (-COO − Na + ) is now shifted to 1601 cm −1 .…”