Co-adsorption behavior of Cr(III) and Cd(II) via direct application of argillaceous limestone.

Pore volume and surface diffusion model (PVSDM) applied for single and binary dye adsorption systems

Synergistic adsorption of Pb2+ and CrO42− on an engineered biochar highlighted by statistical physical modeling

Application of AlMCM-41 for competitive adsorption of methylene blue and rhodamine B: Thermodynamic and kinetic studies

AlMCM-41 was applied for adsorption of methylene blue (MB) and auramine (AU) in single and binary component systems. In the single component systems, AlMCM-41 represents higher adsorption capacity for MB than AU with the maximal adsorption capacity of 2.07×10 −4 and 1.15×10 −4 mol/g at 25 ˚C for MB and AU, respectively. In the binary component system, MB and AU exhibit competitive adsorption onto the adsorbent. In single and binary component systems, kinetic and adsorption isotherm studies demonstrate that the data are following pseudo-second-order kinetic model and Langmuir isotherm. Also, in both cases, kinetic data is fairly described by two-step diffusion model. Effect of solution pH on the adsorption of MB and AU in single and binary component systems was studied and the results were described by electrostatic interactions.

Eliminating different pharmaceutical contaminants simultaneously from wastewater has become a crucial environmental issue. In this regard, the shift from the conventional methods of removing single pollutant to implementing a system that simultaneously removes multiple contaminants is required. In pursuit of this goal, functionalized biochar (FBC) was prepared from bamboo sawdust to simultaneously remove pharmaceutical pollutants in batch and fixed-bed sorption systems. FBC exhibited a greater removal capacity for acetaminophen (ACM) (192.43 mg/g) compared to ciprofloxacin (CIP) (70.95 mg/g), as predicted by the Langmuir isotherm model. The competitive Langmuir isotherm model, employed for the binary component, predicted a maximum adsorption capacity of 125.31 mg/g for ACM and 65.44 mg/g for CIP. The adsorption capacity ratio (qm binary/qm single < 1) suggests an antagonistic behavior of these pollutants when they co-exist in the water matrix. On the other hand, the single and binary component adsorption of ACM and CIP was best described by pseudo-second-order kinetic model, indicating that the adsorption process was mainly controlled by the chemisorption process. Fixed-bed column study showcased the maximum bed capacity of ACM (172.48 mg/g) and CIP (147.67 mg/g), with the highest respective removal efficiency of 44.23% and 37.86% in the binary component adsorption system. However, the single-component column adsorption system achieved a higher removal efficiency of 65.83% (ACM) and 42.59% (CIP). These results indicate that the simultaneous removal of ACM and CIP depends on the unique molecular properties of ACM/CIP and their interactions with the adsorbent. Hence, the as-synthesized FBC has been proven effective for the simultaneous removal of ACM and CIP from various water matrices.

A batch system was applied to study the adsorption behavior of methylene blue (MB) and rhodamine B (RB) in single and binary component systems on natural zeolite. In the single component systems, the zeolite presents higher adsorption capacity for MB than RB with the maximal adsorption capacity of 7.95×10−5 and 1.26×10−5 mol/g at 55°C for MB and RB, respectively. Kinetic studies indicated that the adsorption followed pseudo‐second‐ order kinetics and could be described by a two‐step diffusion process. For the single component systems, the adsorption isotherm could be fitted by the Langmuir model. In the binary component system, MB and RB exhibit competitive adsorption on the zeolite. The adsorption is approximately reduced to 50% and 60% of single component adsorption systems of MB and RB, respectively at an initial concentration of 6×10−6 mol·L−1 at 25°C. In the binary component system, kinetic and adsorption isotherm studies demonstrate that the experimental data are following pseudo‐second‐order kinetics and Langmuir isotherm and kinetic data are fairly described by a two‐step diffusion model. Effect of solution pH on adsorption of MB and RB in both single and binary component systems was studied and the results were described by electrostatic interactions.

Interaction between congo red and copper in a binary adsorption system: Spectroscopic and kinetic studies

The adsorption of cadmium and lead ions from the synthesis wastewater with the activated carbon: Optimization of the single and binary systems

Photocatalytic production of hydrogen in single component and mixture systems of electron donors and monitoring adsorption of donors by in situ infrared spectroscopy

Study of competitive adsorption of malachite green and sunset yellow dyes on cadmium hydroxide nanowires loaded on activated carbon

Nano-size core-shell magnetic SO₃H-functionalized covalent organic frameworks via a functional defect strategy for cationic dye purification: Adsorption behavior and mechanism.

A Fe-Mn oxide-microbe combined biochar (FM-DB) was prepared to simultaneously remove Cd(Ⅱ) and As(Ⅲ) contamination in an aqueous system. In the FM-DB, the best ratio of Fe-Mn oxide (FMBO) and carya cathayensis shell biochar (CCSB) was 3%+3%. The material had good acid resistance, mechanical strength, and mass transfer performance, and the maximum removal rates for Cd(Ⅱ) and As(Ⅲ) in the binary system were 77.29% and 99.94%, respectively. Characterization confirmed that the FM-DB was successfully prepared and had a rich functional group structure. The single-factor adsorption test results for Cd(Ⅱ) and As(Ⅲ) showed that the composite material had a certain adsorption capacity affected by initial pH, equilibration time, and initial concentration for Cd(Ⅱ) and As(Ⅲ) under different conditions. The adsorption isotherm and kinetic data indicated the adsorption equilibrium time for Cd(Ⅱ) and As(Ⅲ) was 3.5 h and 8 h, and the maximum capacity was 59.27 mg·g-1and 84.73 mg·g-1, respectively. The adsorption of Cd(Ⅱ) and As(Ⅲ) was mainly affected by the electron exchange, electron sharing, and complexation on the surface of the material. The whole adsorption process was a combination of single-layer adsorption and multi-layer adsorption on an uneven surface. The adsorption process was a multi-step process, including outer surface diffusion and inner particle diffusion. In addition, comparing the removal rate of composite materials in the single-component system and the binary system, a mutual promotion of adsorption between Cd(Ⅱ) and As(Ⅲ) was found under the binary system. In conclusion, oxide-microbe combined biochar could be an efficient adsorption material and was suitable for the remediation of aqueous system pollution caused by Cd(Ⅱ) and As(Ⅲ).

Diatomite was slightly modified with a sodium hydroxide solution. The resulting material was characterized by using energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and nitrogen adsorption-desorption isotherms. The so-treated diatomite has a high specific surface area (77.8 m2/g) and a high concentration of isolated silanol groups on the surface, and therefore, its adsorption capacity increases drastically in both the single and binary adsorption systems for rhodamine B and methylene blue. The binary system is more effective than the single system, with methylene blue being adsorbed more than rhodamine B. The adsorption process is spontaneous and fits well with the Langmuir isothermal model, and it depends on pH significantly.

Study of aniline/ɛ-caprolactam mixture adsorption from aqueous solution onto granular activated carbon: Kinetics and equilibrium

Adsorption of Cu(II), Pb(II) and humic acid on natural zeolite tuff in single and binary systems