Shrimp waste and its charcoal derivatives were evaluated for the removal of crystal violet. Activation was conducted at 500 °C with phosphoric acid at the 1:2 and 1:3 ratios. Activated charcoals were more porous and had a more roughly surface containing mainly C, O, Ca N, and P. Equilibrium adsorption data were fitted using seven kinetic and six isotherms models. Activation created acidic moieties (>4700 µmol/g) and reduced the point of zero charge (44 m²/g). The best adsorption capacity (208 mg/g) was found for the activated and charred materials, whereas the lowest one (3.9 mg/g) was found for the pyrolyzed material. This research creates the possibility to deal with two environmental problems: (i) the reuse of shrimp waste and (ii) the removal of water pollutants such as crystal violet.

Mid-high-frequency ultrasound (200–1000 kHz) eliminates organic pollutants and also generates H₂O₂. To take advantage of H₂O₂, iron species can be added, generating a hybrid sono-Fenton process (sF). This paper presents the possibilities and limitations of sF. Heterogeneous (a natural mineral) and homogeneous (Fe²⁺ and Fe³⁺ ions) iron sources were considered. Acetaminophen, ciprofloxacin, and methyl orange were the target organic pollutants. Ultrasound alone induced the pollutants degradation, and the dual competing role of the natural mineral (0.02–0.20 g L⁻¹) meant that it had no significant effects on the elimination of pollutants. In contrast, both Fe²⁺ and Fe³⁺ ions enhanced the pollutants’ degradation, and the elimination using Fe²⁺ was better because of its higher reactivity toward H₂O₂. However, the enhancement decreased at high Fe²⁺ concentrations (e.g., 5 mg L⁻¹) because of scavenger effects. The Fe²⁺ addition significantly accelerated the elimination of acetaminophen and methyl orange. For ciprofloxacin, at short treatment times, the degradation was enhanced, but the pollutant complexation with Fe³⁺ that came from the Fenton reaction caused degradation to stop. Additionally, sF did not decrease the antimicrobial activity associated with ciprofloxacin, whereas ultrasound alone did. Therefore, the chemical structure of the pollutant plays a crucial role in the feasibility of the sF process.

Antibiotics elimination by some photochemical processes involves ferric ions, but little is discussed about the fundamental aspects of complexation effects on their degradation. This study compares the photodegradation of two fluoroquinolones, three β-lactams, and their ferric complexes in deionized water. The complexed antibiotics were more recalcitrant than the free antibiotics to the solar light action (the photodegradation rate constants diminished by more than 50%). To better study the photodegradation, other experiments considering two representative cases (ciprofloxacin and dicloxacillin) were performed. For ciprofloxacin, as the iron amount was increased from 0 to 7.5 µmol L⁻¹, its photodegradation rate constant decreased from 0.017 to 0.004 min⁻¹. In contrast, for dicloxacillin, the increase in iron concentration (from 0 to 7.5 µmol L⁻¹) accelerated its photodegradation (the rate constant augmented from 0 to 0.0026 min⁻¹). When UVC light was used, the degradations of free and complexed antibiotics were very close, exhibiting values of degradation rate constants between 0.030 and 0.085 min⁻¹. The antimicrobial activity (AA) was eliminated when 90% of ciprofloxacin and 90–95% of dicloxacillin were degraded. The AA removal was associated with structural changes in relevant moieties of antibiotics, such as fluorine and piperazyl ring for ciprofloxacin, or β-lactam ring for dicloxacillin.

A carbonaceous material obtained from wood wastes (SW-Mn) was initially used for the removal of pharmaceuticals in water by a carbocatalytic system. The SW-Mn material adsorbed only 41% of the diclofenac (DCF) and 3% of the valsartan (VAL). Interestingly, SW-Mn activated peroxymonosulfate (PMS) and presented a significant increase in the removal rate of DCF, surpassing 90%, while VAL achieved a 24% removal rate at 20 min of treatment. The carbonaceous material was not effective in activating peroxydisulfate or hydrogen peroxide. Nevertheless, the addition of ultrasound waves at 40 kHz to the carbocatalytic system (SW-Mn +PMS) significantly enhanced VAL degradation, exhibiting a high synergy index (4.98). The routes of the degradation were determined using scavengers, and XPS and EPR analyses, evidencing the main action of singlet oxygen in both carbocatalytic and sonocarbocatalytic systems. It is important to note that radicals also participated in the sonocarbocatalytic process, albeit with a minor contribution. The reuse of SW-Mn was tested during various cycles, showing up to a 39.2% VAL degradation rate after the third consecutive reuse. Moreover, the sonocarbocatalytic system was applied to a sample of irrigation crop water spiked with VAL. The treatment induced a partial elimination of the pollutant due to some interfering effects of the matrix components.

El alto impacto ambiental de los desechos sólidos y líquidos que contienen elementos tóxicos y metales está teniendo un impacto negativo en diversos ecosistemas, este trabajo tiene como objetivo realizar una revisión sistemática y análisis bibliométrico de la producción científica, con la esperanza de comprender la capacidad de retención y absorción de biocarbón, análisis Capacidad de diferentes biochars para ciertos elementos contaminantes incluyendo metales pesados; el análisis bibliométrico se realizó a través de una revisión de las bases de datos web of science (WoS) y Scopus. Los registros obtenidos se analizan utilizando teoría de grafos y herramientas como bibliometrix, Sci2 Tool, Gephi, se dividen en tres categorías: clásica, estructural y reciente, donde se obtienen tres perspectivas: captación de metales pesados, biodisponibilidad y contaminantes; De igual manera, se identificó que el campo de estudio es nuevo. El principal autor es Yang Yi, autores importantes como Geng Yong y Liang Dong cuentan con un H-index bastante alto. Adicionalmente, los países con mayor producción en el tema son: CHINA que ocupa el primer lugar, USA con el segundo lugar y KOREA con el tercer puesto.