KHCO3-activated high surface area biochar derived from brown algae: A case study for efficient adsorption of Cr(VI) in aqueous solution.

The current study aimed to assess the effectiveness of biochar formed from algae in the removal of Cr(VI) through the process of impregnating brown algae Sargassum hemiphyllum with KHCO3. The synthesis of KHCO3-activated biochar (KBAB-3), demonstrating remarkable adsorption capabilities for Cr(VI), was accomplished utilizing a mixture of brown algae and KHCO3 in a mass ratio of 1:3, followed by calcination at a temperature of 700 °C. Based on the empirical evidence, it can be observed that KBAB-3 shown a significant ability to adsorb Cr(VI) within a range of 60-160 mg g-1 across different environmental conditions. In addition, the KBAB-3 material demonstrated the advantageous characteristic of easy separation, allowing for the continued maintenance of a high efficiency in removing Cr(VI) even after undergoing numerous cycles of reuse. In conclusion, the application of KBAB-3, a novel adsorbent, exhibits considerable prospects for effective removal of Cr(VI) from diverse water sources in the near future.

Review on personal protective equipment: Emerging concerns in micro(nano)plastic pollution and strategies for addressing environmental challenges.

The COVID-19 pandemic was caused by the SARS-CoV-2 virus, marking one of the most catastrophic global health crises of the 21st century. Throughout this period, widespread use and improper disposal of personal protective equipment (PPE) emerged as a pressing environmental issue, significantly impacting various life forms. During the COVID-19 pandemic, there was a high rate of PEP disposal. An alarming 1.6 × 106 tons of plastic waste each day has been generated since the onset of the outbreak, predominantly from the inadequate disposal of PPE. The mismanagement and subsequent degradation of discarded PPE significantly contribute to increased non-biodegradable micro(nano)plastic (MNP) waste. This pollution has had profound adverse effects on terrestrial, marine, and aquatic ecosystems, which have been extensively of concern recently. Accumulated MNPs within aquatic organisms could serve as a potential route for human exposure when consuming seafood. This review presents a novel aspect concerning the pollution caused by MNPs, particularly remarking on their role during the pandemic and their detrimental effects on human health. These microplastic particles, through the process of fragmentation, transform into nanoparticles, persisting in the environment and posing potential hazards. The prevalence of MNP from PPE, notably masks, raises concerns about their plausible health risks, warranting global attention and comprehensive exploration. Conducting a comprehensive evaluation of the long-term effects of these processes and implementing effective management strategies is essential.

Occurrence and fate of pharmaceutical pollutants in wastewater: Insights on ecotoxicity, health risk, and state-of-the-art removal.

Pharmaceutical active compound (PhAC) residues are considered an emerging micropollutant that enters the aquatic environment and causes harmful ecotoxicity. The significant sources of PhACs in the environment include the pharmaceutical industry, hospital streams, and agricultural wastes (animal husbandry). Recent investigations demonstrated that wastewater treatment plants (WWTPs) are an important source of PhACs discharging ecosystems. Several commonly reported that PhACs are detected in a range level from ng L-1 to µg L-1 concentration in WWTP effluents. These compounds can have acute and chronic adverse impacts on natural wildlife, including flora and fauna. The approaches for PhAC removals in WWTPs include bioremediation, adsorption (e.g., biochar, chitosan, and graphene), and advanced oxidation processes (AOPs). Overall, adsorption and AOPs can effectively remove PhACs from wastewater aided by oxidizing radicals. Heterogeneous photocatalysis has also proved to be a sustainable solution. Bioremediation approaches such as membrane bioreactors (MBRs), constructed wetlands (CWs), and microalgal-based systems were applied to minimize pharmaceutical pollution. Noteworthy, applying MBRs has illustrated high removal efficiencies of up to 99%, promising prospective future. However, WWTPs should be combined with advanced solutions, e.g., AOPs/photodegradation, microalgae-bacteria consortia, etc., to treat and minimize their accumulation. More effective and novel technologies (e.g., new generation bioremediation) for PhAC degradation must be investigated and specially designed for a low-cost and full-scale. Investigating green and eco-friendly PhACs with advantages, e.g., low persistence, no bioaccumulation, less or non-toxicity, and environmentally friendly, is also necessary.

Removal of heavy metals from aqueous solutions by high performance capacitive deionization process using biochar derived from Sargassum hemiphyllum.

Capacitive deionization (CDI) has been considered as an efficient, energy-saving and environmental friendly technology for water treatment. For the practical application of CDI, high-performance electrode materials beyond standard activated carbon should be developed. In this study, biochar derived from brown algae Sargassum hemiphyllum prepared by pyrolysis at 300-700 °C and then used as the CDI electrode to remove Cu(II) from aqueous solutions. According to the findings, the optimal pyrolysis temperature was 700 °C, and the electrosorption capacity of BAB700 was 75-120 mg·g-1 at an applied voltage of 1.2 V across wide range of initial pH, temperatures and ion types. Moreover, BAB700 also exhibited outstanding ability to electrosorb other heavy metals (Zn(II), Ni(II), and Cd(II)). In addition, the BAB700 retained the Cu(II) removal efficiency of 70 % in 10 cycles. Cu(II) in actual water is completely eliminated with great reproducibility, resulting in a high degree of applicability for water treatment.

Pyrolysis of marine algae for biochar production for adsorption of Ciprofloxacin from aqueous solutions.

Biochars derived from three species of algae was synthesized by impregnating the green algae Ulva Ohnoi, red algae Agardhiella subulata, and brown algae Sargassum hemiphyllum with ZnCl2 chemical activator and employed as a long-term adsorbent for ciprofloxacin (CIP) removal from water. The results revealed that combination of brown algae and ZnCl2 chemical activator (ZBAB) successfully produced mesoporous biochar with excellent physicochemical characteristics and gave the best CIP adsorption capacity. The ZBAB yielded a high CIP adsorption capacity (190-300 mg g-1) under various parameter effects (initial pH, temperature and major ions). Throughought the surface characterization techniques, the proposed adsorption mechanisms were electrostatic interaction, π-π EDA interaction, pore filling and hydrogen bonding. Moreover, not only algal biochars exhibited innovative and potential adsorbent for rapid and effective remediate pollution from water, but combination of algal biomass and ZnCl2 activator also created renewable source of energy from biomass pyrolysis.

Mesoporous and adsorption behavior of algal biochar prepared via sequential hydrothermal carbonization and ZnCl2 activation.

In this study, biochar derived from brown algal Ascophyllum nodosum was synthesized through hydrothermal carbonization (HTC) coupling with ZnCl2 chemical activation and applied as a sustainable adsorbent for antibiotic removal from water exemplified by ciprofloxacin (CIP). Various surface analysis techniques such as Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and zeta potential were used to clarify the surface properties of prepared biochars. The adsorption performance of biochars was investigated using batch adsorption experiments with a variety of parameters (initial pH, ionic types, temperature and water matrixes). The application of prepared biochar in CIP removal showed a good result of adsorption capacity (150-400 mg g-1) in different conditions. Overall, algal biochars, as a product recycled from biowaste, demonstrated a novel and promising adsorbent for effective and sustainable method for removal of antibiotics from water.

Magnetic biochar derived from macroalgal Sargassum hemiphyllum for highly efficient adsorption of Cu(II): Influencing factors and reusability.

In this study, the brown algae Sargassum Hemiphyllum was used as a carbon source for synthesis of magnetic porous biochar via pyrolyzing at high temperature and and doping iron oxide particles (Fe-BAB). Cu (II) species were removed from aqueous solutions using Fe-BAB under various conditions. Fe-BAB demonstrated superior Cu (II) adsorption (105.3 mg g-1) compared to other biochars. On the surface of Fe-BAB, there are several oxygen-containing functional groups, such as -COOH and -OH, which are likely responsible for the excellent heavy metal removal performance. By utilizing magnet, the Fe-BAB can be conveniently separated from the solution and ready for further usage. Multi-adsorption mechanisms were responsible for Cu adsorption on Fe-BAB. Using the magnetic algal biochar for heavy metal removal is feasible due to its high adsorption efficiency and simplicity of separation.