Simultaneous adsorption of ciprofloxacin and Cu2+ using Fe and N co-doped biochar: Competition and selective separation

Carbon nanomaterials for co-removal of antibiotics and heavy metals from water systems: An overview

Pollution resulting from the combination of antibiotics and heavy metals (HMs) poses a significant threat to human health and the natural environment. Adsorption is a promising technique for removing antibiotics and HMs owing to its low cost, simple procedures, and high adsorption capacity. In recent years, various novel carbon nanomaterials have been developed, demonstrating outstanding performance in simultaneously removing antibiotics and HMs. This work presents a comprehensive review of carbon nanomaterials (i.e., carbon nanotubes, graphene, resins, and other nanocomposites) for the co-removal of antibiotics and HMs in water systems. The mechanisms influencing the simultaneous removal of antibiotics and HMs include the bridging effect, electrostatic shielding, competition, and spatial site-blocking effects. These mechanisms can promote, inhibit, or have no impact on the adsorption capacity for antibiotics or HMs. Additionally, environmental factors such as pH, inorganic ions, natural organic matter, and microplastics affect the adsorption efficiency. This review also covers adsorbent regeneration and cost estimation. On the laboratory scale, the cost of the adsorption process primarily depends on the chemical and energy costs of adsorbent production. Our assessment highlights that the carbon-nanomaterial-mediated simultaneous removal of antibiotics and HMs warrants comprehensive consideration from both economic and environmental perspectives.

Remediation of antibiotic pollution in the global environment by iron-based materials activating advanced oxidation processes: A systematic review

Antibiotic pollution and its associated resistance genes have emerged as a global environmental and health concern, with widespread detection in various environmental media such as water, soil, atmosphere, and sediment, as well as in organisms. Hence, it is imperative to develop effective remediation technologies for the targeted treatment of antibiotic pollution to mitigate its environmental and health risks. This paper reviews the status of antibiotic pollution in major countries, territories, and regions worldwide. Addressing the risks cause by antibiotics and their resistance genes and achieving efficient remediation of antibiotic pollutants. Additionally, the study explores the issue of antibiotic use and resistance in detail from a global perspective. It provides a critical scientific foundation for controlling global antibiotic resistance through multi-dimensional integrated analysis. In 2021, 4.71 million deaths globally were attributed to antibiotic resistance, with countries such as India and China being the most affected. It also examined the predominant types and sources of antibiotic pollutants, as well as key remediation technologies for addressing antibiotic contamination. Antibiotics such as amoxicillin and ciprofloxacin are commonly found in surface waters at concentrations ranging from 1 to 120 μg L-1. Furthermore, this paper highlighted the distinctive advantages of advanced oxidation processes (AOPs) in addressing antibiotic pollution, demonstrating removal efficiencies exceeding 90 % under optimal conditions. Our review underscored the pivotal role of iron-based materials and porous biochar in AOPs, showing promising results in various environmental settings. Future research should prioritize the development of multifunctional iron-based composites with improved catalytic stability, environmental compatibility, and recyclability. Moreover, expanding the field-scale application of these materials, particularly in low-resource or high-risk regions, will be essential to translate laboratory successes into global impact. This analysis is designed to inform and guide future initiatives to control and eliminate antibiotic contamination.

A versatile alginate aerogel with spatially separated sorption sites for simultaneously and collaboratively scavenging Pb(II) and tetracycline in wastewater: Insight into behavior and mechanisms in the mixture system

Alleviating combined pollution caused by heavy metals and antibiotics is of great significance for ecological sustainability and human health. It is still quite challenging to simultaneously and efficiently scavenge both pollutants due to their completely different physicochemical properties and the fierce competition between multi-pollutants faced by traditional adsorbents. In present work, a novel alginate-based aerogel microbead (GO/Fe3+-Ca2+-Alg) with specific sorption sites toward these two sorts of pollutants was fabricated via a 'multi-site coupling' strategy. It was found that multifarious sorption sites in the composite synergistically enhanced removal performance of Pb(II) and TC. The adsorption process of Pb(II) was better described by pseudo-second-order kinetics model (R2 = 0.968-0.989) and Langmuir isotherm model (R2 = 0.966-0.996). The maximum adsorption capacity of Pb(II) and TC in their individual systems was 268.04 and 1664.04 mg/g, respectively, superior to most reported sorption materials. Interestingly, in Pb(II)-TC binary system, Pb(II) capture was enhanced by co-existing TC and its adsorption capacity was positively correlated with concentration of co-existing TC, assigning to the formation of ternary complex (adsorbent-TC-Pb(II) or adsorbent-Pb(II)-TC). However, the removal of TC was enhanced with 10 mg/L Pb(II), and hindered with 20-80 mg/L Pb(II) because of the competition effect of Pb(II) and TC. Sequential adsorption as well as Zeta potential experiments were further performed to verify mutual interaction between Pb(II) and TC. More importantly, the as-designed material was applied in treatment of simulated aquaculture wastewater with removal rates above 80 %, showing its great potential for simultaneous and collaborative elimination of Pb(II) and TC in complex wastewater. This work provided unique insights into designing integrated adsorbents for wastewater bearing heavy metals and antibiotics.

Simultaneous removal of heavy metals and antibiotics from anaerobically digested swine wastewater via functionalized covalent organic frameworks

The removal of heavy metal ions and antibiotics from livestock and poultry wastewater has gained significant attention. Developing dual-functional materials capable of simultaneously removing heavy metal ions and antibiotics from wastewater is a promising strategy. In this study, a functionalization approach was proposed to enhance active sites in covalent organic frameworks (COFs), thereby improving their adsorption performance and maintaining photocatalytic activity. Vinyl-functionalized covalent organic frameworks (COFs-V) were first synthesized in a room-temperature solution. Subsequently, 4-mercaptobenzoic acid was introduced into COFs-V via grafting and chelation to prepare COF@COOH, aiming to modify surface active sites. Fourier transform infrared spectroscopy (FTIR) and in-situ X-ray photoelectron spectroscopy (XPS) confirmed the successful introduction of carboxyl groups into COF@COOH, significantly increasing the number of active sites. The performance and mechanism of COF@COOH in the removal of Cu2+, Zn2+, and tetracycline hydrochloride (TC) from swine wastewater were systematically studied. The results revealed that the adsorption capacities of COF@COOH for Cu2+ and Zn2+ reached 19.27 mg/g and 12.95 mg/g, respectively, which were 58 and 29 times higher than those of the unmodified COFs. Additionally, COF@COOH completely degraded TC within 5 min, with 100% photocatalytic degradation efficiency and an apparent rate constant of 1.13 min-1. After five cycles, the adsorption capacities for Cu2+ and Zn2+ and the degradation efficiency of TC remained nearly unchanged, demonstrating the stability of the composite material. This study provides an effective approach for the simultaneous removal of heavy metal ions and antibiotics from swine wastewater.

Adsorption of heavy metals by biochar in aqueous solution: A review

Heavy metal pollution (e.g., Cd, Hg, Pb, Cu, Ni, Zn, As and Cr) has become a crucial issue worldwide. Among various remediation strategies, adsorption is widely recognized for its environmental sustainability, cost-effectiveness, and operational simplicity. In this context, biochar has gained significant attention due to its promising adsorption performance. To systematically support adsorption studies, this review compiled essential models for adsorption experiments, including commonly used adsorption kinetics models, isotherm models, and thermodynamic analysis methods. Moreover, we systematically analyzed key factors affecting heavy metal adsorption by biochar, such as its physicochemical properties, environmental pH, temperature, initial concentration, dosage, and the presence of coexisting ions, to identify the conditions that govern adsorption capacity. In addition, the adsorption performance of biochar toward eight significant heavy metals is reviewed in detail, with a focus on elucidating the underlying mechanisms, including complexation, ion exchange, cation-π bonding, electrostatic interactions, and precipitation. Finally, based on identified research gaps and critical challenges, we discuss emerging research tools, including machine learning and advanced surface modifications, to guide the targeted design of biochar materials for enhanced adsorption capacity.

A Novel G-C3N4 Modified Biogenic Mackinawite Mediated by SRB for Boosting Highly Efficient Adsorption and Catalytic Degradation of Antibiotics in Photo-Fenton Process

FeS-based nanomaterials are widely used in Fenton-like reaction of antibiotics degradation. However, the problems of poor stability and low reusability limit the catalytic efficiency. Herein, the study ingeniously introduced the g-C3N4 into FeS to synthesize g-C3N4@biogenic FeS (CN-BF-1) nanocomposite with strong interaction of iron ions and "N-pots" by the mediation of sulfate reducing bacteria (SRB). Results indicated the g-C3N4 accelerated SRB metabolism and improved the mineralization and stability of FeS to well-crystallized mackinawite. The CN-BF-1 can efficiently adsorb and degrade antibiotics compared with FeS and g-C3N4, and bear a broad pH range which further proved the increase of stability. The toxicity studies showed ciprofloxacin (CIP) degradation solution hardly caused ecotoxicity and induced antibiotic resistance genes, while CN-BF-1 can be regenerated by SRB in this solution with chemical and enzymatic reduction of Fe(III)-mud to achieve efficient CIP degradation (99.9%). Finally, the mechanism part showed that CN-BF-1 can activate H2O2 to form 1O2 and •OH which played the main roles in the catalysis process. The work paves the way for a novel approach to intensify iron-based photo-Fenton system in sustainable remediation of antibiotic wastewater, upon which the high-efficiency removal and non-toxic degradation solution of antibiotic contamination are expected.

Highly Efficient Peroxymonosulfate Electroactivation on Co(OH)2 Nanoarray Electrode for Pefloxacin Degradation

The activation of PMS to produce active species is an attractive technique for antibiotic degradation but is restricted to the low reaction kinetics and high costs. In this work, a cobalt-based catalyst was prepared by in situ electrodeposition to enhance the electrically activated PMS process for the degradation of antibiotics. Almost 100% of pefloxacin (PFX) was removed within 10 min by employing Co(OH)2 as the catalyst in the electrically activated peroxymonosulfate (PMS) process, and the reaction kinetic constant reached 0.52 min-1. The redox processes of Co2+ and Co3+ in Co(OH)2 catalysts were considered to be the main pathways for PMS activation, in which 1O2 was the main active species. Furthermore, this strategy could also achieve excellent degradation efficiency for other organic pollutants. This study provides an effective and low-cost strategy with no secondary pollution for pollutant degradation.

Recent advances in catalyst design, performance, and challenges of metal-heteroatom-co-doped biochar as peroxymonosulfate activator for environmental remediation

The escalation of global water pollution due to emerging pollutants has gained significant attention. To address this issue, catalytic peroxymonosulfate (PMS) activation technology has emerged as a promising treatment approach for effectively decontaminating a wide range of pollutants. Recently, modified biochar has become an increasingly attractive as PMS activator. Metal-heteroatom-co-doped biochar (MH-BC) has emerged as a promising catalyst that can provide enhanced performance over heteroatom-doped and metal-doped biochar due to the synergism between metal and heteroatom in promoting PMS activation. Therefore, this review aims to discuss the fabrication pathways (i.e., internal vs external doping and pre-vs post-modification) and key parameters (i.e., source of precursors, synthesis methods, and synthesis conditions) affecting the performance of MH-BC as PMS activator. Subsequently, an overview of all the possible PMS activation pathways by MH-BC is provided. Subsequently, Also, the detection, identification, and quantification of several reactive species (such as, •OH, SO4•-, O2•-, 1O2, and high valent oxo species) generated in the catalytic PMS system by MH-BC are also evaluated. Lastly, the underlying challenges associated with poor stability, the lack of understanding regarding the interaction between metal and heteroatom during PMS activation and quantification of radicals in multi-ROS system are also deliberated.

Highly Adsorptive Removal of Ciprofloxacin and E.coli inactivation using Amino acid Tryptophan Modified Nano-gibbsite

Adsorption of essential amino acid, Tryptophan (Tryp) on synthesized gibbsite nanoparticles and their applications in eliminating of antibiotic ciprofloxacin (CFX) and bacteria Escherichia coli (E.coli) in aqueous solution. Nano-gibbsite which was successfully fabricated, was characterized by XRD, TEM-SAED, FT-IR, SEM-EDX and zeta potential measurements. The selected parameters for Tryp adsorption on nano-gibbsite to form biomaterial, Tryp/gibbsite were pH 11, gibbsite dosage 20 mg/mL and 1400 mg/L Tryp. The optimum conditions for CFX removal using Tryp/gibbsite were adsorption time 60 min, pH 5, and 20 mg/mL Tryp/gibbsite dosage. The CFX removal significantly raised from 63 to 90% when using Tryp/gibbsite. The Freundlich and pseudo-second-order models achieved the best fits for CFX adsorption isotherm and kinetic on Tryp/gibbsite, respectively. The amount of CFX increased with increasing ionic strength, suggesting that both electrostatic and non-electrostatic interactions were important. After four reused time, CFX removal was greater than 66%, demonstrating that Tryp/gibbsite is reusable with high performance in removing CFX. The application in bacterial activity in term of E.coli reached greater than 98% that was the best material for bacteria inactivation. The present study reveals that Tryp/gibbsite is an excellent bio-material for removing CFX and E.coli.

Adsorption of sulfamethoxazole and lincomycin from single and binary aqueous systems using acid-modified biochar from activated sludge biomass

The extensive use of pharmaceuticals has raised growing concerns regarding their presence in surface waters. High concentrations of sulfamethoxazole (SMX) and lincomycin (LIN), as commonly prescribed antibiotics, persist in various wastewaters and surface waters, posing risks to public health and the environment. Biochar derived from accessible biowaste, like activated sludge biomass, offers a sustainable and eco-friendly solution to mitigate antibiotic release into water systems. This study investigates the effectiveness of H3PO4-modified activated sludge-based biochar (PBC) synthesized through microwave (MW) heating for the adsorption of SMX and LIN antibiotics. The synthesis parameters of PBC were optimized using a central composite design considering MW power, time, and H3PO4 concentration. Characterization results validate the efficacy of the synthesis process creating a specific surface area of 365 m2/g, and well-developed porosity with abundant oxygen-containing functional groups. Batch and dynamic adsorption experiments were piloted to assess the adsorption performance of PBC in single and binary antibiotic systems. Results show that PBC exhibits a higher affinity for SMX rather than LIN, with maximum adsorption capacities of 45.6 mg/g and 26.6 mg/g, respectively. Based on kinetic studies chemisorption is suggested as the primary mechanism for SMX and LIN removal. Equilibrium studies show a strong agreement with the Redlich-Peterson isotherm, suggesting a composite adsorption mechanism with a greater probability of multilayer adsorption for both antibiotics. Hydrogen bonding and π-π electron sharing are suggested as the prevailing adsorption mechanisms of SMX and LIN on the modified biochar. Furthermore, a dynamic adsorption system was replicated using a fixed bed column setup, demonstrating effective removal of SMX and LIN from pure water and real wastewater samples using PBC-loaded hydrogel beads (PBC-B). These findings serve as crucial support for upcoming studies concerning the realistic application of sludge-based biochar in the removal of antibiotics from water systems.

Effective stabilization of heavy metals in solid waste and sludge pyrolysis using intercalated-exfoliated modified vermiculite: Experiment and simulation study

Pyrolysis is effective in reducing the volume of solid waste and sludge, and produces less pollutants than incineration and landfill, but the process still suffers from heavy metal pollution. Four types of intercalated-exfoliated modified vermiculite (UIV, DIV, TIV and 3IV) were prepared using urea, dimethylsulfoxide, tributyl phosphate and 3-aminopropyltriethoxysilane as intercalators for the control of Cd, Cr, Cu, Pb and Zn in municipal sewage sludge (MSL), paper mill sludge (PML), municipal domestic waste (MWA) and aged refuse (AFE). The larger the interlayer spacing of the vermiculite, the more favorable the retention of heavy metals. 3IV was the most effective additive, with an average retention of more than 75 % of all heavy metals at 450 ℃ for the four raw materials. Cr, Cu, Pb and Zn were all at low potential ecological risk (Pr), while Cd was moderate or considerable Pr, and the addition of 3IV reduced the Pr. Distribution of intercalators between vermiculite interlayers was haphazard, and interlayer spacing results were close to those of the experiment (except for tributyl phosphate). The reactive electrons mainly flowed from the Highest Occupied Molecular Orbital (HOMO) of vermiculite flakes to the Lower Unoccupied Molecular Orbital (LUMO) of heavy metal chlorides. In contrast, the reactive electrons mostly flowed from the HOMO of heavy metal oxides to the LUMO of vermiculite flakes. Heavy metal oxides were more readily adsorbed on vermiculite flakes than heavy metal chlorides, and the adsorption capacity of Cr and Zn was stronger than that of Cd, Pb and Cu.

Synthesis of X@DRHC (X=Co, Ni, Mn) catalyst from comprehensive utilization of waste rice husk and spent lithium-ion batteries for efficient peroxymonosulfate (PMS) activation

Highly efficient resource recycling and comprehensive utilization play a crucial role in achieving the goal of reducing resource wasting, environmental protection, and achieving goal of sustainable development. In this work, the two kinds waste resources of agricultural rice husk and metal ions (Co, Ni, and Mn) from spent lithium-ion batteries have been skillfully utilized to synthesize novel Fenton-like catalysts. Desiliconized rice husk carbon (DRHC) with rich pore structure and large specific surface area from rice husk has been prepared and used as scalable carrier, and dandelion-like nanoparticles cluster could be grown in situ on the surface of the carrier by using metal ions contained waste water. The designed catalysts (X@DRHC) as well as their preparation process were characterized in detail by SEM, TEM, BET, XRD and XPS, respectively. Meanwhile, their catalytic abilities were also studied by activating potassium peroxomonosulfate (PMS) to remove methylene blue (MB). The results indicate X@DRHC displays excellent degradation efficiency on MB with wide pH range and stable reusability, which is suitable for the degradation of various dyes. This work has realized the recycling and high-value utilization of waste resources from biomass and spent lithium-ion batteries, which not only creates an efficient way to dispose waste resources, but also shows high economic benefits in large-scale water treatment.

Degradation of sulfanilamide in aqueous solution by ionizing radiation: Performance and mechanism

Sulfonamide (SA) is an emerging contaminants and the efficient treatment of SA containing wastewater remains a challenge. Herein, SA degradation by gamma irradiation has been systematacially studied. SA (10 mg/L) could be totally removed with 1.5 kGy irradiation. Quenching experiments demonstrated that •OH and eaq- were the predominant for SA degradation. SA degradation was reduced with initial concentration increasing, and the removal was faster with pH increasing in the range of 3.1-10.8. The coexisting matters affected SA degradation through changing reactive species, and the introduction of SO42- and Cl- enhanced SA degradation, while CO32- had a negative impact on SA degradation, and the degradation was insignificantly affected when adding humic acid. Gamma irradiation could remain effective in real water matrixes. In conjunction with LC-MS analysis and DFT calculation, possible degradation pathways for SA were proposed. Gamma irradiation could reduce the toxicity of SA, while several byproducts with more toxic were also formed. Furthermore, gamma/priodate (PI) process was promising to enhance SA degradation and mineralization. k value increased by 1.85 times, and mineralization rate increased from 19.51% to 79.19% when adding PI. This study suggested that ionizing radiation was efficient to eliminate SA in wastewater.

Enhanced adsorption of roxarsone on iron-nitrogen co-doped biochar from peanut shell: Synthesis, performance and mechanism

Efficient removal of organic arsenic (roxarsone, ROX) from wastewater is highly demanded on the purpose of human health and environmental protection. This work aims to prepare Fe-N co-doped biochar (Fe-N-BC) via one-pot hydrothermal method using waste peanut shell, FeCl3·6H2O and urea, followed by pyrolysis. The effect of Fe-N co-doping on biochar's physicochemical properties, and adsorption performance for ROX were systematically investigated. At the pyrolysis temperature of 650 °C, Fe-N-BC-650 shows a significantly increased specific surface area of 358.53 m2/g with well-developed micro-mesoporous structure. Its adsorption capacity for ROX reaches as high as 197.32 mg/g at 25 °C, with > 90 % regeneration efficiency after multiple adsorption-desorption cycles. Correlation and spectral analysis revealed that the pore filling, π-π interactions, as well as hydrogen bonding play the dominant role in ROX adsorption. These results suggest that the Fe-N co-doped biochar shows great potential in the ROX removal from wastewater with high efficiency.