Search

To obtain crystal products with ideal morphology and better quality, it is important to fully understand and grasp the affecting mechanism of solvents on crystal morphology. In this work, the interactions between solvent/solute molecules and different crystal faces of pyriproxyfen are investigated by a combination of experiments and molecular simulations. It is found that pyriproxyfen crystals grow into a lamellar morphology in methanol and ethanol, while the crystal grows into a three-dimensional shuttle morphology in n-butanol and n-heptane. Molecular simulations reveal that the molecular arrangement of crystal faces makes the alcohol hydroxyl adsorption sites exposed in different degrees, and the (002) face is more sensitive to alcohol hydroxyl than other faces. The adsorption of alcohol hydroxyl groups hinders the growth of crystal planes, so (002) and (102) faces become the main crystal planes in methanol and ethanol, and the lamellar crystal is formed. The developed knowledge of the growth mechanism based on the interaction between the solvent and crystal interface can be conducive to the further optimization of the pyriproxyfen crystal products.

Cu-BTC, one of the metal–organic frameworks (MOFs), has been applied to remove the cationic dye methylene blue (MB) and anionic dye methyl orange (CR) from contaminated water. Liquid phase adsorption experiments were conducted and the maximum adsorptive capacity was determined. Various conditions were evaluated, including initial dye concentration, contact time, solution pH, and temperature. The Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and isotherm constant calculation. It was found that the Cu-BTC adsorption capacities of MB and CR are much higher than those of the other types of MOFs and adsorbents. Maximum equilibrium adsorption capacities of 143.27 and 877.19 mg/g for MB and CR were achieved. Three simplified kinetic models including pseudo-first-order, pseudo-second-order, and intra-particle diffusion equations were used to investigate the adsorption process. The pseudo-second-order equation was followed for adsorption of MB and CR on Cu-BTC. Te...

A new type of metal–organic porous material (Ni/Cu–BTC) has been successfully synthesized by a solvothermal approach for the first time. The as-synthesized materials were characterized using XRD, SEM, ICP, and TGA analyses and N2 adsorption at 77 K. The Ni/Cu–BTC was applied to the adsorption of anionic dye congo red (CR) from aqueous solution, and from the experimental data, adsorption kinetics and isotherms were obtained. The results showed that a pseudo-second-order kinetic model and the Langmuir adsorption isotherm matched well for the adsorption of CR onto Ni/Cu–BTC. Thermodynamic parameters including free energy, enthalpy, and entropy of adsorption were obtained, and all the results were favorable for the adsorption. Compared with other adsorbents reported in the literature, Ni/Cu–BTC demonstrated a superior CR dye adsorption capability. The results of the present study substantiate that Ni/Cu–BTC is a promising adsorbent for the removal of the dye from wastewater.

Activated carbon derived from finger citron residue (FAC) was tested as a new type of adsorbent for the removal of harmful dyes, namely, the anionic dye methyl orange (MO) and the cationic dye methylene blue (MB), from contaminated water. Liquid-phase adsorption experiments were conducted, and the maximum adsorption capacity was determined. Various conditions were evaluated, including initial dye concentration, adsorbent dosage, contact time, solution pH, and temperature. The Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and to calculate the isotherm constants. It was found that the adsorption capacity of FAC is much higher than those of other types of activated carbons. Maximum equilibrium adsorption capacities of 934.58 and 581.40 mg/g for MO and MB, respectively, were achieved. Three simplified kinetic models, namely, pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations, were used to investigate the adsorption process. The pseudo-seco...