The presented research includes the preparation, characterization, and implementation of magnetic biosorbent (Fe₃O₄/RWB), obtained from ragweed (Ambrosia artemisiifolia) biomass. Fe₃O₄/RWB was examined for the removal of a hazardous dye, malachite green (MG), from an aqueous solution in a batch system. The effects of the experimental parameters—initial dye concentration (10–300 mg/L), contact time (0–120 min), biosorbent dose (1–5 g/L), initial pH (2–10), ionic strength (0–1 mol/L), and temperature (298–318 K) on dye biosorption—were studied. The results showed that increases in biosorbent dose, contact time, and initial pH led to an increase in biosorption efficiency, while the increase in initial dye concentration, the ionic strength, and temperature had the opposite effect. The biosorption kinetics for MG on Fe₃O₄/RWB were analyzed with pseudo-first-order, pseudo-second-order, and Elovich kinetic models, while the Langmuir, Freundlich and Temkin isotherm models were used for equilibrium data analysis. It was observed that the MG biosorption followed the pseudo-second-order kinetic model, whereas the Langmuir model was the best fit for the equilibrium biosorption data of MG, with a Q_max of 34.1 mg/g. the desorption of MG from Fe₃O₄/RWB indicated reusability in five adsorption/desorption cycles, good performance, and potential in practical applications.

The utilization of different natural materials and their application as low-cost biosorbents in water treatments represents an efficient approach in environmental protection. In this study, the biosorption efficiency of Ambrosia-based biosorbents was analyzed before and after modification with magnetite. The biosorption process with both biosorbents was evaluated using the cationic dye Rhodamine B (RB). After 2h of contact time at an initial RB concentration of 25 ppm, the maximum removal efficiency for RB was 59.2% with non-magnetic, and 91.7% with magnetic biosorbent. Quantification of RB was performed using UV-Vis spectroscopy, while FTIR analysis confirmed the biosorption of RB onto both biosorbents. The results of this study demonstrated that Ambrosia-based biosorbents are economical and effective materials for the removal of RB from aqueous solution.

A dispersive solid-phase microextraction (DSPME) method based on amino-functionalized glycidyl methacrylate polymer was developed and optimized for preconcentration of the azo dye Congo Red (CR) from aqueous samples. Key factors affecting extraction efficiency, including sorbent amount, pH, extraction time, ionic strength, and eluent type, were studied. The method demonstrated good linearity, low limits of detection, and high enrichment factors. The DSPME method was successfully applied to tap water and industrial wastewater samples, showing its potential for environmental monitoring of azo dyes.

In this study, amino-modified magnetic polymer sorbent, mPGME-eda, was employed for the sorption of copper (Cu2+), cadmium (Cd2+), and nickel (Ni2+) ions from aqueous solution. The sorption was studied under competitive conditions by varying contact time and initial metal concentration at unadjusted pH (4.2) and 298 K. It was found that sorption capacity increased with the increase of contact time and initial metal concentration. Equilibrium sorption capacities for Cu2+ (1.20 mmol/g) and Cd2+ (1.15 mmol/g) were attained after 360 min, while for Ni2+ (1.01 mmol/g) it was reached after 90 min. It was noticed that metal ions sorption follows a pseudo-second-order kinetic model. The mechanism of sorption was found to be intra-particle diffusion-controlled with an evident influence of liquid film diffusion. Equilibrium sorption data were best fitted with the Langmuir isotherm model.

The main causes of water pollution in the environment are industries which wastewaters contain many pollutants, including synthetic organic dyes. These compounds can be toxic to organisms, and it is important to eliminate them from wastewaters. Biosorption is a sorption method in which the sorbent is of biological origin, the so-called biosorbent. This method is cheap, simple and eco- friendly. In this investigation the biomass of Ambrosia artemisiifolia was used as a biosorbent of synthetic dyes: Malachite Green (MG), Congo Red (CR), and Rhodamine B (RB). The effectiveness of the analyzed biosorbent was monitored by UV-Vis spectroscopy. The biosorbents were characterized before and after sorption with Fourier Transform Infrared Spectroscopy (FTIR). After 24 h of biosorption, removal efficiency was more than 80 % for all synthetic organic dyes.

Silver, a precious metal used across various industries, can be released into the environment as a byproduct of industrial activities, potentially leading to environmental pollution. Consequently, removing silver from wastewater is crucial for enhancing environmental quality. Porous synthetic polymers (composites), with their high specific surface area and unique physico-chemical properties, have garnered interest as effective sorbents in environmental protection. Glycidyl methacrylate (GMA)-based composites are widely used in various applications such as sorbents (of metals, organic compounds, etc.), enzyme supports, and in biomedicine. The main objectives of this study were the synthesis, characterization, and investigation of the antimicrobial activity of a novel GMA/Ag composite. For the synthesis of the composite, GMA as the monomer, and the crosslinker trimethylolpropane trimethacrylate (TMPTMA) were used, followed by functionalization with diethylenetriamine (DETA). Silver was incorporated into the composite by sorption from 0.1 M AgNO3 solution at pH 5, and 25°C, for 24h. The synthesized composite was characterized using Fourier-transform infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). The antimicrobial activity of the GMA/Ag composite was assessed using the agar-well diffusion method against different microorganisms, including representatives of Gram-negative (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus), yeast (Candida albicans), and fungi (Aspergillus niger). The results of antimicrobial tests indicated that the GMA/Ag composite displayed good antimicrobial activity against the analyzed microbes, and it can potentially be used for biomedical applications, in the food and pharmaceutical industries, in the treatment of wastewater, etc.