This study presents the first investigation of Mimosa pigra L. seeds, a readily available invasive plant in Vietnam, as a biosorbent for methylene blue (MB) removal. The seed powder was characterized using FT-IR, SEM–EDX, XRD, particle-size distribution, and N 2 adsorption–desorption analyses. Its adsorption performance was evaluated under different solution pH and adsorbent dosages, followed by kinetic and equilibrium isotherm analyses. The adsorption kinetics were best described by the pseudo-second-order model, with an initial uptake rate of 13.7 mg g -1 min -1 . The Langmuir model provided the best fit to the equilibrium data, yielding a maximum adsorption capacity of 121.9 mg g -1 . Comparative characterization before and after adsorption, together with the adsorption results, suggested that electrostatic attraction, hydrogen bonding, and π–π interactions contributed to MB uptake. Overall, raw M. pigra seed powder is a promising, low-cost biosorbent because of its simple preparation and reasonable reusability.
In this study, two different biocomposites (Bsp–GOS and Pe–GOS) were created by immobilizing Green Olive Stone with Bacillus sp. and Pleurotus eryngii . The removal of methylene blue (MB) from aqueous solutions was investigated using these materials. The structural and surface properties of the biocomposites were characterized by FTIR, SEM, and EDX analyses. FTIR results showed that hydroxyl, carbonyl, and ether groups played an active role in the biosorption mechanism; SEM–EDX analyses showed porous structure and morphological changes occurring on the surface. Experimentally, the effects of parameters such as pH, contact time, initial dye concentration, and biocomposite amount on biosorption efficiency were evaluated. The optimum pH of Bsp–GOS and Pe–GOS biocomposites was determined as 7.0 and 6.0, respectively. The contact time was determined as 60 minutes for both biocomposites. Isotherm analyses showed that Bsp–GOS fit the Langmuir model better, while Pe–GOS fit the Freundlich model better. Kinetic data showed a fit to a pseudosecond-order model for both systems. In conclusion, the developed biocomposites were evaluated as biosorbents prepared from agricultural waste.
Arsenic is a widely occurring geogenic contaminant in groundwater in many places around the globe. The incorporation of high-adsorption iron oxides into activated carbon is an important area of research for arsenic removal. The present study describes an activated carbon-based iron-oxide nanocomposite (AC-IONC) synthesized via co-precipitation and evaluated for the removal of arsenic from aqueous systems. The characterization of AC-IONC using BET, SEM-EDS, FTIR, FESEM, and XRD confirmed the successful integration of iron oxide nanoparticles onto the porous activated carbon matrix, yielding a high surface area (947.97 m 2 /g), structural stability, and abundant functional groups, all of which are favorable for adsorption. Batch adsorption experiments were conducted to assess the influence of pH, adsorbent dosage, kinetics, and initial arsenic concentration. The kinetics of adsorption at various pH levels were investigated. The modeling studies using kinetic adsorption models revealed that the adsorption process followed a pseudo-second-order kinetics model (R 2 = 0.98, NAPE = 2.6%). The adsorption equilibrium datasets were best fit by the Langmuir isotherm model (R 2 = 0.99, NAPE = 2.81), suggesting monolayer adsorption on a homogeneous surface, with a maximum adsorption capacity of 8.08 mg/g. The combined adsorption kinetic and equilibrium (CAKE) model was used to predict the adsorption kinetics and equilibrium at various initial concentrations and times. The regeneration studies showed a modest decrease in adsorption capacity after repeated adsorption-desorption cycles, indicating the AC-IONC’s moderate regeneration efficiency. A spiked study conducted with real water samples showed a marked reduction in adsorption capacity, which suggested that adsorption was reduced in the presence of other co-existing ions. In summary, the AC-IONC demonstrated strong potential as an efficient method for arsenic remediation in water treatment applications.
Phenolic compounds are hazardous pollutants that threaten aquatic ecosystems and human health, necessitating effective removal from industrial effluents. This study evaluates phenol adsorption using raw Jacaranda biomass (BJ) and phosphoric acid-activated biochar (H-BJ). Activation at 600 °C produced a highly porous adsorbent with a Brunauer–Emmett–Teller (BET) surface area of 791 m 2 /g and enriched surface functionalities, as confirmed by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, X-ray diffraction analysis, pH point of zero charge (pH pzc ), and BET analyses. FTIR indicated the formation of additional hydroxyl groups that enhanced phenol interaction. Adsorption behavior followed Langmuir and Freundlich isotherms and pseudo-second-order kinetics, indicating uniform and predominantly physical adsorption. Maximum capacities reached 40.127 mg/g for BJ and 61.732 mg/g for H-BJ at 600 °C. Thermodynamic parameters confirmed a spontaneous, exothermic process with increased entropy. Application of H-BJ600 (2% dosage) to olive mill wastewater achieved 74% phenolic removal with a q e of 45.42 g/g. These findings demonstrate the potential of Jacaranda -derived activated biochar as an efficient adsorbent for phenol remediation and wastewater treatment.
Pharmaceutical contamination of water sources presents serious risks to environmental sustainability and public health, requiring the development of affordable and effective wastewater treatment methods. Common treatment technologies often fail to fully remove pharmaceutical residues and are hindered by high energy use, operational costs, and the production of harmful by-products. Recently, research has increasingly focused on repurposing industrial wastes such as fly ash and sludge as low-cost, high-surface-area adsorbents for removing pharmaceuticals. This review thoroughly examines pharmaceutical pollutants, including their sources, environmental impacts, and concentration levels in wastewater. It assesses both traditional and emerging removal methods, with a particular emphasis on adsorption. The potential of raw and modified industrial waste materials as sustainable adsorbents is critically analyzed, considering key factors influencing adsorption, such as pH, temperature, initial concentration, as well as adsorption kinetics and isotherms. The review also emphasizes how these materials can be integrated into the circular economy by repurposing them for water purification. Recommendations for future research include enhancing adsorbent stability, reusability, and selectivity through modifications like magnetization, acid treatment, chitosan addition, and zeolitization, along with verifying their scalability. The results reinforce the importance of waste-based adsorbents in achieving sustainable water management.
