Insight into the key factors and mechanism of excellent tetracycline adsorption on amorphous cobalt carbonate nanosheets.

The extensive use of tetracyclines (TCs) has led to their widespread distribution in the environment, causing serious harm to ecosystems because of their toxicity and resistance to decomposition. Adsorption is presently the principal approach to dispose of TCs, and the development of excellent adsorbents is crucial to TC removal. Herein, a novel amorphous cobalt carbonate hydroxide (ACCH) was successfully prepared by a one-step solvothermal method, which was identified as Co(CO3)0·63(OH)0.74·0.07H2O. The ultimate adsorption capacity of ACCH for TC reaches 2746 mg g-1, and the excellent adsorption performance can be maintained over a wide pH (3.0-11.0) and temperature (10-70 °C) range. Moreover, ACCH also exhibits a wonderful adsorption performance for other organic contaminants, such as ciprofloxacin and Rhodamine B. The TC adsorption process can be reasonably described by the pseudo-second-order kinetic model, intraparticle model and Langmuir isothermal model. The experimental results in this work suggest that the excellent adsorption performance of ACCH is ascribed to the large specific surface area, alkaline characteristics and numerous functional groups of ACCH. Accordingly, this work provides a promising strategy for the development of highly-efficient adsorbents and demonstrates their application prospects in environmental remediation.

Preparation of Activated Biocarbons from Cones and their Potential Application for Adsorption of Antibiotics (Tetracycline).

The pine cones (PC), spruce cones (SC) and fir cones (FC) were used for biocarbons preparation. Chemical activation with sodium hydroxide was applied to prepare activated biocarbons. All the materials under investigation were characterized by the N2 adsorption, scanning electron microscopy (SEM), elemental analysis (CHNS), infrared spectroscopy (ATR FT-IR), and the Boehm's titration method. Moreover, pHpzc (the point of zero charge) was determined. It was shown that cones are a good, cheap precursor from which biocarbons with a developed porous structure, characterized by good adsorption properties, can be obtained. All the obtained adsorbents are characterized mainly by a microporous structure. Moreover, they contain both acidic and basic surface functional groups (acidic ones prevail over basic ones). The tested activated biocarbons have large specific surface area values ranging from 578 to 1182 m2 g-1. The efficacy of selected materials in the adsorption of an essential contaminant of increasing concern, tetracycline (TC), was investigated. The experimental data were described using the Langmuir and Freundlich adsorption isotherm models. The maximum adsorption capacity of the tested biocarbons ranges from 200 to 392 mg g-1. Thermodynamic studies proved that adsorption is a spontaneous and endothermic process. In summary, economical and environmentally friendly adsorbents were obtained.

Novel conjugated microporous polymers for efficient tetracycline adsorption: insights from theoretical investigations.

This paper presents a detailed theoretical understanding of the noncovalent interactions between antibiotics tetracycline and conjugated microporous polymer (CMP), which is important to understand the recent experimental finding of efficient removal of antibiotics by CMP materials. We show that the co-work of π-π and H-π interactions determines the final equilibrium structures, when a tetracycline molecule spontaneously adsorbs to the surface or within the pores of the CMP network at physisorption distances. The binding energies for tetracycline/CMP systems are calculated to be -0.31 âˆ¼ -1.15 eV, demonstrating the reliability of the adsorption. The electronic structures of CMP nanostructures remain basically undamaged upon the tetracycline adsorption. The replacement of benzothiadiazole unit with S and N heteroatoms to the phenyl moiety in the linker effectively enhanced the molecular polarity of CMP molecule and increases the interaction area between tetracycline and CMP network, consequently enhancing the average binding energies notably. Our calculations provide useful theoretical guidance for design of novel carbon-based porous adsorbents with good adsorption performance to remove residual tetracycline and other antibiotics in water.

Structuring alginate/dopamine powder into macroscopic aerogel microsphere for exceptional removal of tetracycline from water: Performance and mechanisms.

Aerogel was selected as one of IUPAC Top Ten Emerging Technologies in Chemistry in 2022, and has attracted tremendous concerns of scientists in removal of emerging contaminants. In this work a novel Fe3+ cross-linked alginate aerogel (SA/DA-Fe3+) with multiple sorption sites were facilely fabricated and applied for highly efficient removal of tetracycline (TC) from water. Results showed that Fe3+ and DA cooperatively improve adsorption of TC and TC was efficiently removed over a broad pH range of 4-8. The kinetics process can be better described by a chemisorption controlled pseudo-second-order kinetics model and Langmuir isotherm equation with characteristics of monolayer coverage. The fitted qmax value of TC at ambient temperature was 804.6 mg g-1 higher than those of other reported adsorbents. Multiple interactions including π-π EDA, complexation, hydrogen bonding, electrostatic attraction, etc. were involved in adsorption process. Moreover, SA/DA-Fe3+ aerogel exhibited satisfactory stability, reusability, and recyclability for consecutive applications. Most importantly, after consecutively running for >1000 h with dynamic sorption capacity over 500 mg g-1, the packed-column was still not saturated, manifesting its great potentials for treating actual wastewaters. Thus, above superiorities make SA/DA-Fe3+ a promising candidate adsorbent for treating TC-containing wastewater.

Polyethylene terephthalate hydrolysate increased bacterial cellulose production.

A major challenge to large-scale production and utilization of bacterial cellulose (BC) for various applications is its low yield and productivity by bacterial cells and the high cost of feedstock. A supplementation of the classical expensive Hestrin and Schramm (HS) medium with 1 % polyethylene terephthalate ammonia hydrolysate (PETAH) resulted in 215 % high yield. Although the physicochemical properties of BC were not significantly influenced, the BC produced in 1 % PETAH-supplemented HS medium showed a higher surface area, which showed 1.39 times higher adsorption capacity for tetracycline than BC produced in HS medium. The 1 % PETAH-supplemented HS medium respectively enhanced the activity of α-UDP-glucose pyrophosphorylase and α-phosphoglucomutase by 30.63 % and 135.24 % and decreased the activity of pyruvate kinase and phosphofructokinase by 40.34 % and 52.63 %. The results of this study provide insights into the activation mechanism of Taonella mepensis by PETAH supplementation for high yield and productivity of BC.

Efficient adsorption of tetracycline in aquatic system by thermally-treated sediment.

The disposal of dredged sediment is a considerable challenge for environmental protection and resource utilization. In this study, the dredged sediment was thermally-treated to prepare as adsorbent and utilized for tetracycline adsorption. Sediments based adsorbents under different pyrolysis temperature and atmosphere (N2 and limited oxygen) were obtained and 600 °C and N2 atmosphere (600AN) exhibited maximum TC adsorption capacity (15.45 mg/g). SEM, N2 adsorption-desorption isotherm, XRD, FTIR and XPS analysis suggested larger pore volume, relatively higher surface area, effective pore size distribution and abundant surface functional groups were the main reasons. Moreover, the influence of key adsorption parameters, including adsorbent dosage, initial pH, coexisting ions, ionic strength, contact time, initial TC concentration and ambient temperature had also been investigated. Results revealed that TC adsorption by 600AN were more consistent with pseudo-second order kinetic and Freundlich isothermal models. Combined with characterization results, which reasonably inferred that the adsorption mechanisms of 600AN were mainly involved pore-filling effect, hydrogen bonding interaction and π-π EDA interaction. This work has provided a low-cost, high efficiency and promising method for the dredged sediment reduction and resource recovery.

Adsorption modeling, thermodynamics, and DFT simulation of tetracycline onto mesoporous and high-surface-area NaOH-activated macroalgae carbon.

Activated carbon (ENAC) was prepared by NaOH activation, using macroalgae (Enteromorpha clathrate) as raw material. The prepared activated carbon has a large surface area (1238.491 m2 g-1) and its total pore volume and average pore size are 0.6823 cm3g-1 and 2.2038 nm, respectively. The ENAC was characterized by SEM, FTIR, BET and XPS. The effects of contact time (0-960 min), initial tetracycline (TC) concentration (50-500 mg L-1), temperature (30-50 °C) and initial pH (2-11) on TC adsorption were evaluated. The adsorption isotherm and adsorption kinetics were discussed. Results showed that the adsorption isotherm was the Langmuir model, and the adsorption process can be described by the pseudo-second-order model. The N2 adsorption-desorption isotherm was type IV, indicating that the activated carbon had mesoporous structure. Thermodynamic analysis showed that the adsorption process was endothermic and spontaneous. The maximum adsorption capacity of TC was 381.584 mg g-1. Density functional theory (DFT) was used to simulate and analyze the adsorption process, and the influence of different types of N on the adsorption was expounded. The results showed that there are electrostatic interactions, π-π interactions and hydrogen bonding between the adsorbent and TC. These results indicated that the prepared ENAC had a great application prospect in the removal of antibiotics from aqueous solution.

La/LaF3 co-modified MIL-53(Cr) as an efficient adsorbent for the removal of tetracycline.

Chromium based metal-organic framework (MIL-53(Cr)) has enormous potential in the removal of organic contaminants from aqueous solutions due to its outstanding water stability, whereas its poor adsorption capacity limits the application. In this study, La/LaF3-MIL-53(Cr) was successfully synthesized by taking the advantages of La doping and LaF3 encapsulation with one-step hydrothermal method. Diverse analysis tools were utilized to verify that La not only existed in the framework, but also was loaded in the pores in the form of LaF3. The adsorption experiment results demonstrated that 0.3-La/LaF3-MIL-53(Cr) exhibited significantly improved adsorption capacity by four times compared with the pristine MIL-53(Cr) material. XPS and FTIR revealed that the affinity of La to tetracycline was significantly stronger than that of Cr and the excellent dispersion of LaF3 in the material may also be the cause of the increase in adsorption capacity. This study described a simple method to combine two different forms of modification and the modified material was potential for tetracycline adsorption.

Effective tetracycline removal from liquid streams of dairy manure via hierarchical poly (vinyl alcohol-co-ethylene)/polyaniline metal complex nanofibrous membranes.

Antibiotic residues from animal wastes enter underground and surface water streams, posing high risks to public health. Novel technologies capable of removing the residues from the matrix of concern such as animal waste should be developed. This research investigates the development of nanofiber absorbent for removing tetracycline (TC) antibiotic residues from liquid streams of dairy manure produced in a typical dairy farm. Hierarchically structured nanofibrous adsorbent was developed through growing a uniform polyaniline (PAni) nanodots on poly (vinyl alcohol-co-ethylene) (EVOH) nanofiber membrane (NFM). Moreover, Cu2+ ions were chelated on the developed EVOH/PAni-Cl NFM to improve TC adsorption efficiency and selectivity. The TC adsorption capacities of EVOH/PAni-Cl-Cu2+ and EVOH/PAni-Cl) NFM were 1100 mg g-1 and 600 mg g-1 within 120 min., respectively. The NFMs adsorption efficiency was investigated using dairy wastewater. Initial TC concentrations in dairy wastewater sample varied between 20 and 50 ppm. The EVOH/PAni-Cl-Cu2+ NFM showed TC removal of 86% from dairy manure samples at 25 ppm initial TC concentration within 60 min. during batch mode treatment. Results showed that the dynamic binding efficiency of 450 mg g-1 can be achieved at an initial TC concentration of 50 ppm. Furthermore, the NFM displayed efficient chemical and physical stability even after 8 cycles of reusing without significant changes in its performance or hazardous Cu2+ leaching.

High mesoporosity phosphorus-containing biochar fabricated from Camellia oleifera shells: Impressive tetracycline adsorption performance and promotion of pyrophosphate-like surface functional groups (C-O-P bond).

In China, more than 3.5 million tons of Camellia oleifera discarded shells are produced every year. This work first prepared phosphorus-containing biochar (PBC) from C. oleifera shells and was successfully applied to the efficient removal of tetracycline (TC) from solutions. The prepared PBC exhibits superior TC adsorption capacity of 451.5 mg/g, and TC uptake rapidly reached 315.5 mg/g at the first 5 min (C0 = 50 mg/L). Furthermore, PBC also shows excellent applicability to the broad range pH value (1-9) and superior selective removal in the presence of various high concentration coexisting ions (1 mM). Mechanisms underlying TC adsorption were also put forward, and analysis suggested that pyrophosphate-like surface functional groups (C-O-P bond) played a critical role in this process. Notably, treating pharmaceutical wastewater with PBC can efficiently reduce chemical oxygen demand (COD) and total organic carbon (TOC) concentration below the discharge standard of China (GB21904-2008).

Highly efficient nitrate and phosphorus removal and adsorption of tetracycline by precipitation in a chitosan/polyvinyl alcohol immobilized bioreactor.

Single denitrification using bacteria has been widely investigated, but few studies have focused on the simultaneous removal of nitrate, phosphorus. and tetracycline. Strain L2, an iron-reducing bacteria, was immobilized using chitosan/polyvinyl alcohol to simultaneously remove nitrate and phosphorus. The effects of carbon/nitrogen ratio (1:1, 1.5:1, and 2:1), initial Fe2+ concentration (0, 15, and 30 mg·L-1), and HRT (2, 4, and 6 h) were assessed in bioreactors and optimum conditions were established. Results showed that the nitrate and phosphorus removal efficiency reached 100.00% (2.697 mg·L-1·h-1) and 81.93% (1.533 mg·L-1·h-1) under the conditions of carbon/nitrogen of 2:1, Fe2+ concentration of 30 mg·L-1 and HRT of 6 h. The precipitation of bioreactor, which identified as FeOOH by XRD, had significant adsorption on tetracycline. The results of high-throughput sequencing indicated that strain L2 played a significant role in denitrification. This bioreactor provided effective method for the treatment of polluted water contaminated by nitrate, phosphorus, and tetracycline.

Pharmaceutical analysis by a novel spinel ferrite nanocomposite derived from a biomaterial-based activated carbon.

Microwave-assisted activated carbon was fabricated from lentil waste (LW) by K2CO3 chemical activation at optimum production conditions and the synthesized optimal activated carbon (LWAC) with a high surface area (1875 m2/g) was used as a matrix for spinel ferrite composite production. CuFe2O4 nanoparticles were embedded to LWAC and a novel magnetic composite material (M-LWAC) was synthesized. A detailed structural and textural analysis of M-LWAC was made by using various characterization techniques. M-LWAC was also used as an effectual remover for tetracycline (TC) bearing wastewater with 384.62 mg/g of adsorption capacity. Kinetic, isotherm and thermodynamic analyses indicated the fast, effective and spontaneous adsorption of TC by M-LWAC.

Removal of tetracycline from polluted water by chitosan-olive pomace adsorbing films.

This paper focuses on the removal of tetracycline from polluted water by chitosan-olive pomace adsorbing films. More specifically, both raw olive solid wastes (olive pomace) and the olive solid wastes/chitosan composite were compared and used for this purpose. Adsorption capacities values of 16 mg × g-1 and 1.6 mg × g-1 were obtained for the two adsorbents respectively. However, chitosan/olive pomace is proposed as suitable for environmental applications avoiding the dispersion of the pomace blocked inside the chitosan film. To detail the adsorption process, the effect of several experimental parameters such as the pH values, ionic strength, amount of adsorbent and pollutant and temperature values was investigated. The results showed that the adsorption process improved increasing the pH values, with a maximum at pH 8, and it was negatively affected by the presence of salts that retarded the adsorption. Indeed, the desorption of tetracycline was obtained in a MgCl2 2 M solution. So, a low-cost and cleaner approach, fundamental for the pollutant recovery and for an adsorbent safe reuse, for several cycles of adsorption/desorption, transforming a waste in resource is presented. The kinetics, isotherms models of adsorption and the thermodynamic parameters (ΔG°, ΔH° and ΔS°) were also evaluated observing that the physisorption of the pollutant occurred with and an endothermic character (ΔH°â€¯> 0) with ΔG°â€¯< 0 and ΔS°â€¯> 0. The use of Advanced Oxidation Processes was proposed as possible alternative to the tetracycline recovery, obtaining its degradation after the desorption. With the present paper, the alternative reuse of olive pomace is reported avoiding its disposal in the environment claiming its potential in the removal/recover of emerging contaminants from water.

A novel Biochar modified by Chitosan-Fe/S for tetracycline adsorption and studies on site energy distribution.

A novel wasted sludge-based Biochar modified by Chitosan and Fe/S (BCFe/S) was prepared for tetracycline (TC) removal from water. To investigate the similarities and differences in adsorption behaviors between Biochar and BCFe/S, characterization, kinetics, isotherms and thermodynamics were discussed. The studies on site energy distribution (SED) were also presented. The results showed that the maximum TC adsorption amount was 51.78 mg/g for Biochar, while it was 183.01 mg/g for BCFe/S-4. Meanwhile, electrostatic attraction, π-π stacking, pore filling, silicate bonding and hydrogen bonding were the main adsorption mechanisms for TC removal by Biochar. Besides above mechanisms, chelating and ion exchange were also accounted for adsorption mechanisms for TC uptake by BCFe/S-4. Moreover, SED results revealed that the surface of Biochar was more homogeneous while the surface of BCFe/S-4 was more heterogeneous at higher temperature. Findings of this work could offer valuable information in designing adsorbents and investigating adsorption mechanisms.