Removal of beta-lactam antibiotic in water environment by adsorption technique using cationic surfactant functionalized nanosilica rice husk

Adsorption characteristics of individual and binary mixture of ciprofloxacin antibiotic and lead(II) on synthesized bamboo-biochar

Adsorption of individual and a binary mixture of ciprofloxacin antibiotic (CFX) and lead ion, Pb(II) on bamboo biochar was investigated in this study. Bamboo biochar which was successfully fabricated by pyrolysis was carefully characterized by XRD, SEM, TEM, BET, FT-IR, XPS and zeta potential measurements to confirm the porous structure and high specific surface area of 134 m2 g-1. Individual and simultaneous adsorption of CFX and Pb(II) on synthesized bamboo biochar was systematically studied by batch technique. The optimum experimental parameters for CFX and Pb(II) simultaneous adsorption were pH 6, 5.0 mg mL-1 bamboo-biochar dosage, contact time 120 min while that were found to be, adsorbent dosage of 2.5 mg mL-1 and 60 min contact time, pH 3 for CFX and pH 4 for Pb(II) individual adsorption. The maximum adsorption efficiencies of binary mixture CFX and Pb(II) on bamboo biochar were achieved 99.9 and 90.8%, respectively while the very high adsorption capacities fitted by Langmuir model were found to be 183.6 and 285.7 mg g-1 for Pb(II) and CFX, respectively. Adsorption mechanisms of CFX and Pb(II) on bamboo biochar were discussed in details based on surface charge changes and isothermal data.

An enzymatically modified adsorbent derived from an agro-residue mitigates the environmental risks of toxic antibiotic mixtures

This study developed an enzymatically modified adsorbent derived from pine bark (PBEM), an agricultural residue feedstock, for the adsorptive removal of antibiotic contaminants. PBEM was synthesized by optimizing the feedstock selection and modifying it using fungal crude enzymes sustainable recoverable from natural sources. PBEM rapidly removed the antibiotics tetracycline and sulfamethoxazole from a mixed solution much more rapidly (4-99 times faster) and in higher quantities (2-5 times higher) than without enzyme modification. The outperforming removal performance was validated using adsorption kinetics and isotherm parameters over five repeated cycles. Analytical chemistry identified four novel byproducts (BPs) generated in the antibiotic mixture. Quantitative structure-activity relationship analysis revealed that two of these BPs with considerable toxicity potential comparable to the parent compounds, but they were transient and eventually removed using PBEM. As a result, PBEM effectively controlled the toxic effects of the original antibiotics and their BPs much more rapidly than the control adsorbent with no enzyme coating, as illustrated by experimental antimicrobial toxicity testing. These results thus demonstrate the potential of PBEM for both removing various antibiotic residuals via physicochemical adsorption and enzymatic breakdown and completely detoxifying solutions containing antibiotics and their BPs.

A new way to combine carboxymethyl cellulose with Fe: Application and mechanism analysis

A new, effective powdered adsorbent (CMCFe) for removing oxytetracycline (OTC) was synthesized successfully in an acidic environment using a thermal fusion technique. CMC-Fe underwent comprehensive SEM, EDS, FT-IR, XRD, XPS, TGA, and BET analyses before and after adsorbing OTC. These studies systematically examined preparation variables such as CMC and FeCl3 ratios, acetic acid quantity, reaction duration, and temperature. Batch adsorption experiments evaluated how well CMC-Fe absorbs OTC, with detailed analyses of adsorption mechanisms through kinetics, isotherms, and thermodynamic methods. Characterization analysis of CMC-Fe pre- and post-OTC adsorption confirmed its stability, high adsorption capacity, and the presence of OTC on its surface. Within 2 h, batch adsorption experiments demonstrated that CMC-Fe could adsorb up to 1005 mg·g-1 of OTC. Examination of kinetics, isotherms, and thermodynamics showed that OTC adsorption by CMC-Fe is a complex, multilayered, endothermic process where physical adsorption prominently contributes to OTC removal. Key factors driving the adsorption process include chelation involving Fe2+, Fe3+, and OTC, π-π stacking, pore filling, and strong electrostatic interactions. CMC-Fe exhibits exceptional adsorption capacity for OTC, demonstrating strong environmental adaptability and promising potential for pollutant removal in aquatic environments.

Influence of goethite on the fate of antibiotic (tetracycline) in the aqueous environment: Effect of cationic and anionic surfactants

Over the last decades, the release and occurrence of organic pollutants in aquatic systems have become a major global concern due to their bioaccumulation, toxicity, and adverse effects on the ecosystem. Tetracycline (TC), a widely used antibiotic, is often found at high concentrations in the aqueous environment and tends to bind with the natural colloids. Post-COVID-19 pandemic, the release of surfactants in the environment has increased due to the excessive use of washing and cleaning products. This study systematically investigated the interaction of goethite with TC in the absence and presence of anionic (sodium dodecyl sulfate, SDS) and cationic (cetyltrimethylammonium bromide, CTAB) surfactants. The impact of various environmental parameters like pH, ionic strength, temperature, and organic matter was also studied. It was observed that SDS has drastically increased TC sorption onto goethite from 11 mg/g to 19 mg/g, while CTAB had the opposite effect. To delineate the goethite-TC interaction mechanisms, FTIR with two-dimensional correlation analysis (2D-COS) was performed. The pH of the solution was crucial in the presence of SDS, while ionic strength did not affect the interaction process. The sorption process was endothermic, as evidenced by the increase in sorption capacity with the rise in the temperature. The presence of organic matter hinders the sorption of TC onto goethite, which is also observed in river water where the organic content is very high. Overall, our study helps to predict the fate of organic pollutants like antibiotics in aqueous environments in the coexistence of surfactants and iron oxyhydroxides.

Influence of CTAB Reverse Micellar Confinement on the Tetrahedral Structure of Liquid Water

The effect of confinement on the tetrahedral ordering of liquid water plays a vital role in controlling their microscopic structure and dynamics as well as their spectroscopic properties. In this article, we have performed the classical molecular dynamics simulations of four different CTAB/water/chloroform reverse micelles with varied water content to study how the tetrahedral ordering of nanoscale water inside reverse micellar confinement influences the microscopic dynamics and the structural relaxation of water···water hydrogen bonds and its impact on the low-frequency intermolecular vibrational bands. We have noticed from the results obtained from simulated trajectories the lowering trends of tetrahedral ordering of water pools in reverse micellar confinements as we move from bulk to confined and strictly confined environments. We have observed that the order of confinements significantly altered the relaxation pattern of water···water hydrogen bonds present in the nanoscale water pool of reverse micelles. The recrossing related to hydrogen bond dynamics can effectively explain the relaxation pattern of C HB WW ( t ) under confinement. The Br-1···water hydrogen bond depicts a much slower relaxation compared to the water···water hydrogen bonds inside reverse micelles. We have also explored the correlation between the tetrahedral ordering of nanoscale water pools and the relaxation of water···water hydrogen bonds with the 50 cm-1 band for water inside reverse micelles. The computations reported that compared to bulk water, the band appearing at 50 cm-1 for O···O···O triplet bending is nonuniformly blue-shifted by 18-45 cm-1 for the nanoscale water pool inside reverse micelles, and the intensity of the band drops from bulk to confined and strictly confined environments, which indicates the reduced tendency of such triplet formation. It is observed that a significant intensity variation at the 200 cm-1 band correlates with the effect of confinement on the tetrahedral ordering of the water pool inside reverse micelles. So, our observations support the influence of strictly confined environments on the tetrahedral water structure to adopt the quasi-two-dimensional water network and experience restricted longitudinal translations. It is further noticed that the 500 cm-1 librational band is also found to be blue-shifted by 71-112 cm-1 for the water pool in reverse micelles, and the extent of the shift being more noticeable for strictly confined environments correlates excellently with the sluggish relaxation of water···water hydrogen bonds in such environments.

Performance of magnetic nanocomposite based on xanthan gum-grafted-poly(acrylamide) crosslinked by borax for the effective elimination of amoxicillin from aquatic environments

This study evaluated the effectiveness of using nanocomposite (NCs) of xanthan gum grafted polyacrylamide crosslinked Borax - iron oxide nanoparticle (XG-g-pAAm-CL-Borax-IONP) to remove the amoxicillin antibiotic (AMX) from an aquatic environment. To confirm the structural characteristics of the prepared XG-g-pAAm-CL-Borax-IONP NCs, unique characterization methods (XRD, FT-IR, FE-SEM, EDX, BET, TGA, Zeta, and VSM) were used. Adsorption experimental setups were performed with the influence of solution pH (4-9), the effect of adsorbent dose (0.003-0.02 g), the effect of contact time (5-45 min), and the effect of initial AMX concentration (50-400 mg/L) to achieve the most efficient adsorption conditions. Based on the Freundlich isotherm model, XG-g-pAAm-CL-Borax-IONP NCs provided the maximum AMX adsorption capacity of 1183.639 mg/g. This research on adsorption kinetics also established that the pseudo-second-order model (R2 = 0.991) is outstanding compatibility with the experimental results. AMX adsorption on the NCs may occur through intermolecular hydrogen bonding, diffusion, and trapping into the polymer network. Even after five cycles, these NCs still displayed the best performance. Based on these results, XG-g-pAAm-CL-Borax-IONP NCs may be a viable material for the purification of AMX from contaminated water.

Highly Efficient Removal of 2,4,5-Trichlorophenoxyacetic Acid by Adsorption and Photocatalysis Using Nanomaterials with Surface Coating by the Cationic Surfactant

Extensive removal of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) using titania (TiO2) nanoparticles by adsorption and photocatalysis with a surface coating by cetyltrimethylammonium bromide (CTAB) is reported. The CTAB-coated TiO2 nanoparticles (CCTN) were characterized by FT-IR, zeta-potential measurements, and UV-vis diffuse reflectance spectroscopy (UV-vis-DRS). 2,4,5-T removal increased significantly after surface modification with CTAB compared with bare TiO2 nanoparticles. Optimal parameters affecting 2,4,5-T removal were found to be pH 4, CCTN dosage 10 mg/mL, and adsorption time 180 min. The maximum adsorptive removal of 2,4,5-T using CCTN reached 96.2% while highest adsorption capacity was 13.4 mg/g. CCTN was also found to be an excellent photocatalyst that achieved degradation efficiency of 99.2% with an initial concentration of 25 mg/L. The removal mechanisms of 2,4,5-T using CCTN by both adsorption and photocatalysis are discussed in detail based on changes in functional group vibrations and surface charge. Our results indicate that CCTN is an excellent material for 2,4,5-T removal in water by both adsorption and photocatalysis.

From wastewater to clean water: Recent advances on the removal of metronidazole, ciprofloxacin, and sulfamethoxazole antibiotics from water through adsorption and advanced oxidation processes (AOPs)

Antibiotics released into water sources pose significant risks to both human health and the environment. This comprehensive review meticulously examines the ecotoxicological impacts of three prevalent antibiotics-ciprofloxacin, metronidazole, and sulfamethoxazole-on the ecosystems. Within this framework, our primary focus revolves around the key remediation technologies: adsorption and advanced oxidation processes (AOPs). In this context, an array of adsorbents is explored, spanning diverse classes such as biomass-derived biosorbents, graphene-based adsorbents, MXene-based adsorbents, silica gels, carbon nanotubes, carbon-based adsorbents, metal-organic frameworks (MOFs), carbon nanofibers, biochar, metal oxides, and nanocomposites. On the flip side, the review meticulously examines the main AOPs widely employed in water treatment. This includes a thorough analysis of ozonation (O3), the photo-Fenton process, UV/hydrogen peroxide (UV/H2O2), TiO2 photocatalysis, ozone/UV (O3/UV), radiation-induced AOPs, and sonolysis. Furthermore, the review provides in-depth insights into equilibrium isotherm and kinetic models as well as prospects and challenges inherent in these cutting-edge processes. By doing so, this review aims to empower readers with a profound understanding, enabling them to determine research gaps and pioneer innovative treatment methodologies for water contaminated with antibiotics.

Effect of cations on monochlorobenzene adsorption onto bentonite at the coexistence of Tween 80

The effect of several prevalent cations (including Na+, K+, Mg2+, Ca2+, Al3+, and Fe3+) on the adsorption of monochlorobenzene (MCB) onto bentonite was investigated at the coexistence of nonionic surfactant Tween 80 (T80) in surfactant-enhanced remediation (SER). They are all favorable for MCB and T80 adsorption, especially Mg2+ and Ca2+. Adsorption of MCB is strongly depended on T80 micelles. When its concentration exceeds the solubility, MCB is easier to bind with T80 micelles and be adsorbed by bentonite. Acidic environment can facilitate MCB and T80 adsorption, but the effect of cations on the adsorption is most significant under alkaline conditions. Adsorption capacity of MCB increases first followed by a slight decrease with increasing cations concentrations. The maximum adsorption rate of MCB determined is about 68.4% in a solution containing Mg2+ in the isothermal adsorption of MCB, while it is only 6.8% in a cation-free solution. Various characterizations showed that cations mainly changed the repulsion between bentonite particles and T80 micelles and the agglomeration and structure of bentonite, thus affecting the adsorption of MCB and T80 micelles. Our research demonstrated the nonnegligible promotion of MCB adsorption on bentonite by cations and acidic environment, which will adversely affect SER efficiency.

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.

Synthesis and application of wetland plant-based functional materials for aqueous antibiotics removal

Wetlands have been widely used in wastewater treatment and restoration of water bodies due to their ecological characteristics and functions. However, large amounts of plant residues are produced in wetlands every year and their treatment are facing large challenge. Synthesis of wetland plant-based functional materials (WPBFMs) has emerged as promising method for treating and recycling wetland plant residues. These functional materials have been demonstrated to effectively remove aqueous pollutants, such as antibiotics and dyes in wastewater. This article provides a comprehensive review on synthesis and application of WPBFMs for aqueous antibiotics removal and gives guidance for future research in treatment and recycling of wetland plant residues. It is shown that emergent plant residues are the mostly used raw materials for WPBFMs synthesis. The main products are biochar and its composites, cellulose and its modified materials, which are synthesized by slow pyrolysis and alkali treatment-bleaching treatment method, respectively. The removal pathways and mechanisms for aqueous antibiotics by WPBFMs are also discussed. Finally, the challenges and perspectives are discussed for synthesis and application of WPBFMs for antibiotics removal.

Static adsorption and photocatalytic degradation of amoxicillin using titanium dioxide/hydroxyapatite nanoparticles based on sea scallop shells

The objective of this study is to investigate the efficiency of two processes for the amoxicillin removal through static (batch) adsorption and photocatalytic degradation onto the prepared samples. Three solid materials as photocatalyst and/or adsorbent were synthesized viz. nanotitanium dioxide (NT) prepared by the sol-gel method, scallop shells-based nanohydroxyapatite (NP), and nanotitanium dioxide/nanohydroxyapatite composite (NTP). The physicochemical and morphological properties of the prepared samples were tested by TGA, XRD, DRS, ATR-FTIR, nitrogen adsorption/desorption isotherm, zeta potential, SEM, and TEM. The major operational conditions were optimized for catalyst or adsorbent mass, pH, shaking time, initial amoxicillin (AMX) concentration, power of UV lamp, and temperature. The results illuminated that NTP achieved the highest adsorption capacity (88.46 mg/g) at 20 ℃ and AMX adsorption onto all the solid materials was well applied by Langmuir, Temkin, pseudo-second order, and Elovich models. The maximum desorption percent (98%) was attained by acetone. The degradation percent of AMX reached 85.3 and 99.5% for NT and NTP, respectively, using 0.9 g/L of catalyst dosage through 90 min. AMX photodegradation onto the catalysts' surface was well fitted by Langmuir-Hinshelwood, Arrhenius, and Eyring-Polanyi models with endothermic, physical, and nonspontaneous nature of photocatalysis process. NTP acts as a promising adsorbent and photocatalyst for the antibiotics' removal in wastewater.

Influence of the surface modification of granular-activated carbon synthesized from macauba on heavy metal sorption

Adsorption on activated carbon is a promising technique for the treatment of low-concentration heavy metal pollutants in water with high efficiency and simple operation. However, commercial-activated carbon is often associated with high costs. Therefore, much attention has been given to activated carbon derived from low-cost agricultural and residual biomass. In this work, adsorption of Zn, Cd, and Pb ions in aqueous solutions was conducted using granular-activated carbon obtained from macauba palm, biomass waste of biofuel production, after surface modification using different methods. The adsorbents were obtained in granular form which facilitates all steps of the use, recovery, and reuse of the material, differently from the powdered-activated carbon normally used. The materials were characterized by using XPS, elemental analysis, N₂ sorption (BET method), and zeta potential measurements. Such techniques allowed observation of the functionalization of the carbon surface. The materials presented high adsorption capacities when compared to other works in the literature, with a capacity of approximately 7.69, 8.42, and 1.63 mmol g^-1 for Zn²⁺, Cd²⁺, and Pb²⁺, respectively. In addition, the materials showed a high capacity to be reused, removing 75% of Pb and 99% of both Cd and Zn after 4 cycles.

Sustainable colorimetric/luminescent sensors enabled by armored lipid nanoparticles

In this study, we developed a highly stable polymeric vesicle using a nanosilica-armor membrane to achieve a sustainable colorimetric/luminescent response. The silica armor can be grown directly as ~ 5 nm spherical nanoparticles on the surface of the diacetylene (DA) vesicle with liposomal structure. This can be accomplished via the modified Stöber reaction in pure water on a layer of amine linkers deposited on the vesicles. Once formed, the structural stability of the DA vesicles dramatically increased and remained so even in a dried powder form that could be stored for a period of approximately 6 months. Then, redispersed in water, the armored vesicles did not agglomerate because of the electric charge of the silica armor. After polymerization, the polydiacetylene (PDA) vesicles maintained an average of 87.4% their sensing capabilities compared to unstored vesicles. Furthermore, the silica membrane thickness can be controlled by reiteration of the electrostatic layer-by-layer approach and the direct hydrolysis of silica. As the number of silica armor membranes increases, the passage of the stimuli passing through the membranes becomes longer. Consequently, three layers of silica armor gave the PDA vesicles size-selective recognition to filter out external stimuli. These discoveries are expected to have large-scale effects in the chemo- and biosensor fields by applying protective layers to organic nanomaterials.

Reducing the negative impact of ceftriaxone and doxycycline in aqueous solutions using ferrihydrite/plant-based composites: mechanism pathway

The adsorption of ceftriaxone (CET) and doxycycline (DOX) from aqueous solution using ferrihydrite/plant-based composites (silica rice husk) to reduce their negative impact on the ecosystem was adequately studied. On the other hand, phosphate and humic acid are often found in water and soil; in view of this, their effects on the adsorption of CET and DOX were investigated. The results showed that the removal of ceftriaxone decreased with an increase in pH, while that of doxycycline did not. Ferrihydrite with 10% silica rice husk (Fh-10%SRH) has the highest maximum adsorption capacity of 139 and 178 mg g^-1 for CET and DOX, respectively, at room temperature based on Liu's adsorption isotherm. This implies that the presence of silica rice husk increases CET and DOX uptake due to an increase in the pore volume of FH-10%SRH. The results showed that phosphate had a significant inhibition role on CET adsorption and minor on DOX, whereas humic acid salt affected neither case. Increase in temperature up to 333 K favored the adsorption of both contaminants. The proposed adsorption mechanisms of ceftriaxone are electrostatic interaction, n-π interaction, and hydrogen bond, while that of DOX entails n-π interaction and hydrogen bond.