Corn (Zea mays L.) ranks among the most important cereal crops globally, extensively cultivated for food, animal feed, and industrial applications. Its large-scale production generates substantial amounts of agricultural residues such as cobs, husks, stalks, leaves and other, which are often underutilized, leading to environmental concerns. Due to their high carbon content, lignocellulosic structure, and abundant availability, these residues represent a sustainable and low-cost raw material for the synthesis of activated carbon. Corn waste-derived activated carbon has emerged as a promising material for the efficient removal of heavy metals from aqueous solutions. Its high surface area, well-developed porosity, and adjustable surface chemistry, referring to the functional groups on the adsorbent surface that can be modified to enhance affinity toward metal ions, facilitate effective adsorption. This review provides a comprehensive overview of (1) the potential of corn waste biomass as a precursor for activated carbon production, (2) methods of carbonization and activation that influence the textural and chemical properties of the resulting adsorbents, (3) adsorption performance for heavy metal removal under varying experimental parameters such as pH, initial concentration, contact time, and adsorbent dosage, (4) adsorption mechanisms responsible for heavy metal uptake. Reported maximum adsorption capacities vary for different metals, ranging from 2.814–206 mg/g for lead, 0.21–87.72 mg/g for cadmium, 9.6246–175.44 mg/g for chromium, and 0.724–643.92 mg/g for copper. Utilizing corn waste not only provides an eco-friendly approach for managing agricultural residues but also supports the development of efficient adsorbents. Nevertheless, challenges such as scaling up production and evaluating adsorbent performance in real wastewater samples remain and require further investigation. Finally, the review highlights key challenges and knowledge gaps in current research and offers recommendations for future studies aimed at advancing the practical application of corn waste–based activated carbons in water treatment.

Optimization of the efficiency of the photocatalytic degradation of organic and pharmaceutical pollutants represents a matter of fundamental and practical interest. The present experimental and DFT study deals with evaluation of OH radical binding energy as a simple computational descriptor of the catalytic activity of d-metal-decorated TiO₂ photocatalysts for the photodegradation of the widely used antibiotic ciprofloxacin. Five d-metals commonly used in catalytic materials (Zr, Pt, Pd, Fe, and Cu) were deposited on the TiO₂ surface, and the obtained photocatalysts were characterized experimentally (XRPD, ICP-OES, and SEM) and theoretically (DFT). Attention was also paid to the mechanistic insights and degradation byproducts (based on UV-Vis spectrometry and LC/MS analysis) in order to obtain systematic insight into their structure/performance relationships and confirm the proposed model of the degradation process based on OH radical reactivity.

(1) Background: An increasing use of pharmaceutics imposes a need for the permanent development of efficient strategies, including the tailoring of highly specific new materials for their removal from the environment. Photocatalytic degradation has been the subject of increasing interest of the researchers in the field. (2) Methods: This paper is focused on the investigation of the possibility to deposit a thin metal layer on a TiO₂ surface and study its photocatalytic performance for the degradation of ciprofloxacin using a combination of theoretical and experimental methods. (3) Results: Based on the extensive DFT screening of 24 d-metals’ adhesion on TiO₂, Cu was selected for further work, due to the satisfactory expected stability and good availability. The (Cu)TiO₂ was successfully synthesized and characterized with XRD, SEM+EDS and UV-Vis spectrophotometry. The uniformly distributed copper on the TiO₂ surface corresponds to the binding on high-affinity oxygen-rich sites, as proposed with DFT calculations. The photocatalytic degradation rate of ciprofloxacin was improved by about a factor of 1.5 compared to the bare non-modified TiO₂. (4) Conclusions: The observed result was ascribed to the ability of adsorbed Cu to impede the agglomeration of TiO₂ and increase the active catalytic area, and bandgap narrowing predicted with DFT calculations.

This work used activated carbon material obtained by chemical activation of abundantly available agricultural sunflower waste residues to remove metol (4-(methylamino) phenol sulfate, MTL) from aqueous solutions. The adsorbent structure was characterized using SEM-EDS and FT-IR spectroscopy. A modified screen-printed carbon electrode (SPCE) with gold nanoparticles synthesized using the Laser Ablation Synthesis in Solution (LASIS) method was used to detect MTL. The successful LASIS formation of gold nanoparticles was confirmed by the specific dark burgundy–red color. TEM measurements showed uniform pseudo-spherical particles with an average diameter of 7.9 ± 0.2 nm. The modified electrode showed improved electrochemical activity, which was confirmed by comparing it with an unmodified electrode using cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode was subsequently used to optimize the MTL detection conditions. UV–Vis spectroscopy was used to optimize the adsorption conditions, with the optimal values for pH and contact time found to be 8 and 120 min, respectively. The electrochemical detection of MTL was performed using differential pulse voltammetry, and the linear calibration range was established for concentrations ranging from 0.73–49.35 µM. The obtained limits of detection (LOD) and quantification (LOQ) were 0.06 µM and 0.2 µM, respectively. The efficiency of MTL removal was 100% after a contact time of 1 min and remained at 100% after 120 min.

Efficient removal of antibiotic residues from the water using environmentally friendly and zero-waste technologies represents an emerging challenge. The increasing development of photocatalytic materials needs a comprehensive and systematic approach to understand the principles behind their performance. In this contribution, the Cu-decorated TiO2 nanoparticles were prepared using various input amounts of Cu (0.5 - 2%), employed for photocatalytic degradation of ciprofloxacin solution (30 mg photocatalyst per 50 mL of solution), and compared to bare TiO2 at the same concentration. The observed performance improvement of investigated photocatalytic material compared to bare TiO2 upon decoration with Cu was discussed from various aspects. Some of them include: morphostructural changes (increase of active surface for photocatalysis upon reduced agglomeration), chemical effects (the improved generation and reactivity of active oxygen species upon modification of their adsorption properties), and modification of photochemical properties of the semiconductor material itself (impact of metal decoration on the band gap structure).

Bisphenol S (BPS) is a synthetic compound frequently used as an alternative to Bisphenol A (BPA) in the manufacture of various plastics and resins. Its widespread use has led to its detection in environmental samples, raising concerns about its potential endocrine-disrupting effects and toxicity. Recent research shows that BPS can leach from consumer products and accumulate in aquatic ecosystems, posing risks to both aquatic organisms and human health. Electrochemical oxidation of BPS has emerged as a promising approach for its degradation. This study examines the electrochemical oxidation of Bisphenol S utilizing SnO₂-MWCNT (multi-walled carbon nanotubes) electrodes in a galvanostatic regime at different current densities (10, 15 and 20 mA cm⁻²). The main objective of this study was to compare the removal efficiency and energy consumption during the degradation of BPS on various current densities. Experimental results indicated that an increase in current density corresponds to a rise in both removal efficiency and energy consumption. However, this observation highlights the necessity for careful optimization to balance efficiency and energy consumption in real-world applications.