Efficient acetaminophen removal from water and hospital effluents treatment by activated carbons derived from Brazil nutshells

Electrochemical Technologies to Decrease the Chemical Risk of Hospital Wastewater and Urine

The inefficiency of conventional biological processes to remove pharmaceutical compounds (PhCs) in wastewater is leading to their accumulation in aquatic environments. These compounds are characterized by high toxicity, high antibiotic activity and low biodegradability, and their presence is causing serious environmental risks. Because much of the PhCs consumed by humans are excreted in the urine, hospital effluents have been considered one of the main routes of entry of PhCs into the environment. In this work, a critical review of the technologies employed for the removal of PhCs in hospital wastewater was carried out. This review provides an overview of the current state of the developed technologies for decreasing the chemical risks associated with the presence of PhCs in hospital wastewater or urine in the last years, including conventional treatments (filtration, adsorption, or biological processes), advanced oxidation processes (AOPs) and electrochemical advanced oxidation processes (EAOPs).

Efficient and selective removal of Ag+ as nano silver particles by the composite of SiO2 supported nano ferrous oxalate

Developing novel environmentally materials with high capacity and selectivity for Ag⁺ adsorption by transforming Ag⁺ to nano silver is important for the recovery of precious metals from Ag-containing solution. The present study systematically studied the Ag ⁺ adsorption process from solution by the composite of SiO₂ supported nano ferrous oxalate (SNFO) synthesized from biotite-containing minerals. Batch experiments, dynamics and isothermal adsorption fitting results showed that Ag⁺ removal behaviours were in accordance with the pseudo-first-order kinetic model and Langmuir model, and the maximal Ag⁺ removal capacity was 223.68 mg/g. Thermodynamic fitting results suggested that Ag ⁺ removal by the composite was a spontaneous and endothermic reaction process. XRD and TEM revealed that the reaction products were consisted of SiO₂ and nano silver particles, and FTIR and XPS results indicated that the Ag⁺ removal mechanisms were attributed to the synergistic reduction interaction between ferrous and the anions of oxalate. Meanwhile, the composite possesses high selectivity for Ag⁺ removal even at low Ag⁺ concentration. Moreover, the size of nano silver particles could be adjusted by different pH values. All above results demonstrated that the composite was an ideal material for selective recovery of Ag⁺ from Ag⁺ containing effluents in the form of nano silver.

Toxicity and remediation of pharmaceuticals and pesticides using metal oxides and carbon nanomaterials

The worldwide development of agriculture and industry has resulted in contamination of water bodies by pharmaceuticals, pesticides and other xenobiotics. Even at trace levels of few micrograms per liter in waters, these contaminants induce public health and environmental issues, thus calling for efficient removal methods such as adsorption. Recent adsorption techniques for wastewater treatment involve metal oxide compounds, e.g. Fe2O3, ZnO, Al2O3 and ZnO-MgO, and carbon-based materials such as graphene oxide, activated carbon, carbon nanotubes, and carbon/graphene quantum dots. Here, the small size of metal oxides and the presence various functional groups has allowed higher adsorption efficiencies. Moreover, carbon-based adsorbents exhibit unique properties such as high surface area, high porosity, easy functionalization, low price, and high surface reactivity. Here we review the cytotoxic effects of pharmaceutical drugs and pesticides in terms of human risk and ecotoxicology. We also present remediation techniques involving adsorption on metal oxides and carbon-based materials.

Preparation and Application of Efficient Biobased Carbon Adsorbents Prepared from Spruce Bark Residues for Efficient Removal of Reactive Dyes and Colors from Synthetic Effluents

Biobased carbon materials (BBC) obtained from Norway spruce (Picea abies Karst.) bark was produced by single-step chemical activation with ZnCl2 or KOH, and pyrolysis at 800 °C for one hour. The chemical activation reagent had a significant impact on the properties of the BBCs. KOH-biobased carbon material (KOH-BBC) had a higher specific surface area (SBET), equal to 1067 m2 g−1, larger pore volume (0.558 cm3 g−1), more mesopores, and a more hydrophilic surface than ZnCl2-BBC. However, the carbon yield for KOH-BBC was 63% lower than for ZnCl2-BBC. Batch adsorption experiments were performed to evaluate the ability of the two BBCs to remove two dyes, reactive orange 16 (RO-16) and reactive blue 4 (RB-4), and treat synthetic effluents. The general order model was most suitable for modeling the adsorption kinetics of both dyes and BBCs. The equilibrium parameters at 22 °C were calculated using the Liu model. Upon adsorption of RO-16, Qmax was 90.1 mg g−1 for ZnCl2-BBC and 354.8 mg g−1 for KOH-BBC. With RB-4, Qmax was 332.9 mg g−1 for ZnCl2-BBC and 582.5 mg g−1 for KOH-BBC. Based on characterization and experimental data, it was suggested that electrostatic interactions and hydrogen bonds between BBCs and RO-16 and RB-4 dyes played the most crucial role in the adsorption process. The biobased carbon materials showed high efficiency for removing RO-16 and RB-4, comparable to the best examples from the literature. Additionally, both the KOH- and ZnCl2-BBC showed a high ability to purify two synthetic effluents, but the KOH-BBC was superior.

River water treatment using electrocoagulation for removal of acetaminophen and natural organic matter

Electrocoagulation (EC) was assessed for removal of acetaminophen and natural organic matter (measured as UV₂₅₄) from river water. Process was assessed for time, electrode materials, inter electrode distance, and voltage. Best conditions for removal of acetaminophen and UV₂₅₄ absorbance were 60 min reaction time, aluminum-aluminum electrodes, 2 cm inter electrode distance, and 9 V. Acetaminophen tested at 1, 2, 5, 10, and 20 mg L^-1 showed that treatment efficiency decreased as the concentration increased. The main mechanism for removal of acetaminophen was H bonding with Al(OH)₃ flocs; this was confirmed by XRD and FT-IR spectrum. Pseudo-second order kinetics model exhibited a good fit on experimental data for acetaminophen removal at different concentrations. Univariate ANOVA indicated statistically significant difference between treatments for acetaminophen removal (F_2.76 = 136, P = <0.001). A significant linear correlation was found between UV₂₅₄ absorbance and acetaminophen removal at different concentrations. Preliminary analysis suggest that EC will cost US$ 0.22/m³ for river water treatment. The lab-scale EC process was compared with a full-scale water treatment plant for removal of natural organic matter. Water treatment plant after multiple levels of purification was not able to fully remove UV₂₅₄ absorbance whereas EC treatment showed good efficiency.

Performance study on adsorptive removal of acetaminophen from wastewater using silica microspheres: Kinetic and isotherm studies

Owing to the global industrialization, a new generation of pharmaceutical pollutants with high toxicity and persistency have been detected. In the present study, silica microspheres, a promising adsorbent has been employed to investigate the extent of removal of prevalent therapeutic acetaminophen, an emerging micropollutant, from wastewater in isolated batch experiments. The BET surface area of the adsorbent was 105.46 m²/g with a pore size of 15 nm. Characterization of adsorbent by scanning electron microscopy analysis revealed the microparticulate nature with a 15 ± 5 μm particle size. Optimization of reaction parameters for enhanced assimilative removal of pollutants was performed and the highest adsorption of 96.7% of acetaminophen with an adsorption capacity of 89.0 mg/g was observed upon contact time of only 30 min. Mild process conditions of pH 5.0, 20 ppm of acetaminophen, temperature of 303 K, and 100 ppm sorbent concentration further aided in the removal process. Obtained data were best corresponded with the Freundlich isotherm (n = 2.685), indicating highly favorable adsorption. Acetaminophen adsorption kinetics obeyed the pseudo second order and feasible energetic changes were yielded through the thermodynamic analysis. Silica microspheres recovery carried out through a single-step desorption process had a 99.14% retrieval ability.

Efficient capture of ReO4- on magnetic amine-functionalized MIL-101(Cr): Revealing from selectivity to mechanism

The efficient decontamination of pertechnetate (⁹⁹TcO₄^-) is an essential task for managing radioactive ⁹⁹Tc in nuclear wastes. Perrhenate, (ReO₄^-), as a nonradioactive analog, exhibits almost identical physicochemical properties as ⁹⁹TcO₄^-. Herein, a novel magnetic amine-functionalized MIL-101(Cr) (NH₂-MIL-101(Cr)@Fe₃O₄) was prepared and used to efficiently remove ReO₄^- from solution for the facile magnetic separation. A series of environmental parameters were considered to investigate the adsorption performance of NH₂-MIL-101(Cr)@Fe₃O₄. Experimental results suggested that NH₂-MIL-101(Cr)@Fe₃O₄ has reached a satisfied adsorption capacity (~401 mg/g) and a very fast adsorption kinetics at pH 7.0. The selectivity for ReO₄^- was maintained even in the presence of interfering anions with relatively high concentrations. ReO₄^- were mainly captured by N-donor sites of the surface-decorated amine via complexation and were trapped in the cavities of modified MIL-101(Cr). NH₂-MIL-101(Cr)@Fe₃O₄ exhibits satisfactory adsorption performance for ReO₄^- and can be conveniently separated from wastewaters after adsorption.

Adsorption of 4-chlorophenol by magnetized activated carbon from pomegranate husk using dual stage chemical activation

Separation under the influence of magnetic field has been widely explored to tackle environmental issues related to centrifuging and filtration. In this work, activated carbon produced from pomegranate husk (PHAC) using dual stage chemical activation was magnetized with iron salts and used for adsorption of 4-chlorophenol (4CP) from the synthetic wastewater. Adsorption experiments were conducted in batch mode to determine the removal efficiency of magnetized activated carbon pomegranate husk (MPHAC) as a function of initial 4CP concentration, solution pH, MPHAC dose, contact time, ionic strength, and temperature. The rough surface of MPHAC containing pores on the surface had a total pore volume of 0.623 cm3/g with a surface area of 1168 m2/g. The 4CP adsorption was highly dependent on ionic strength, solution pH, and temperature; the equilibrium was reached in 60 min of contact time. Kinetic models and equilibrium isotherms were employed to assess the fitness of adsorption data; results were fitted best with the Liu model giving maximum adsorption capacities of 446.89 ± 20.75 and 183.64 ± 17.85 mg/g for 1 and 2 g/L of MPHAC, respectively. For the investigation of the adsorption kinetics, Avrami fractionary-order model showed the best fit of the experimental data compared to other kinetic models.

Fabrication of activated carbon from pomegranate husk by dual consecutive chemical activation for 4-chlorophenol adsorption

In the present work, the fabrication of activated carbon (AC) from pomegranate husk (PHAC) by dual consecutive activation processes with ZnCl2 and NaOH as a chemical agent was studied. After that, the synthesized PHAC was used for adsorption of 4-chlorophenol (4CP) as a highly toxic compound for the human health and the environment. Different analytical techniques characterized the synthesized PHAC using ZnCl2/NaOH. The isotherms of N2 adsorption and desorption showed that total pore volume (Vtotal) and specific surface area (SBET) of PHAC were 0.404 cm3/g and 811.12 m2/g, respectively. The 4CP adsorption by PHAC studies revealed that the highest 4CP removal efficiency was 100% and obtained at 50, 100, and 150 mg/L of 4CP concentration with 2.5 g/L of PHAC. Based on the batch experiments, the highest 4CP removal was achieved at pH 6, 2.5 g/L of PHAC, and contact time of 60 min. The 4CP adsorption data of equilibrium and kinetics were successfully fitted to Langmuir's isotherm and Avrami fractional order.

Efficient removal of Hg2+ from aqueous solution by a novel composite of nano humboldtine decorated almandine (NHDA): Ion exchange, reducing-oxidation and adsorption

Efficient removal of Hg²⁺ from aqueous solution is key for environmental protection and human health. Herein, a novel composite of nano humboldtine decorated almandine was synthesized from almandine for the removal of Hg²⁺. Results showed that the Hg²⁺ removal process followed pseudo-second-order kinetic model and Langmuir equation, and the maximum adsorption capacity was 575.17 mg/g. Furthermore, Hg²⁺ removal by the composite was pH-dependent and low pH value facilitated the removal of Hg²⁺. SEM and HADDF-STEM results suggested a new rod morphology was generated and the adsorbed mercury was mainly enriched into this structure after reaction with Hg²⁺ solution. The removal mechanisms of Hg²⁺ by the composite was pH dependent, and included ion exchange, surface complexation, reduction and oxidation. Our results demonstrated that the composite was an ideal material for Hg²⁺ removal and the transformation ways of mercury related species could be a significant but currently underestimated pathway in natural and engineered systems.

Rapid elimination of trace bisphenol pollutants with porous β-cyclodextrin modified cellulose nanofibrous membrane in water: adsorption behavior and mechanism

A porous β-cyclodextrin modified cellulose nano-fiber membrane (CA-P-CDP) was fabricated and employed to treat the trace bisphenol pollutants (bisphenol A (BPA), bisphenol S (BPS), and bisphenol F (BPF)) in water. The characterization highlighted the porous structure, stable crystal structure, good thermal stability of the obtained CA-P-CDP, as well as abundant functional groups, which could greatly improve the adsorption of bisphenol pollutants and recovery. During the static adsorption process, the adsorbents dosage, temperature and pH showed significant influence on the adsorption performance. At the selected conditions (25 °C, 7.0 of pH and 0.1 g L^-1 of CA-P-CDP dosage), the BPA/BPS/BPF adsorption on CA-P-CDP could rapidly reached the equilibrium in 15 min by following the pseudo-second-order kinetic model, and the maximum adsorption capacities were 50.37, 48.52 and 47.25 mg g^-1, respectively, according to Liu isotherm model. The mechanisms between the bisphenol pollutants and CA-P-CDP mainly involved the synergism of hydrophobic effects, hydrogen-bonding interactions and π-π stacking interactions. Besides, the dynamic adsorption data showed that the volume of treated water for CA-P-CDP (0.58 L) was 14.5 times larger than that of pristine cellulose membrane (0.04 L), revealing satisfactory adsorption performance of trace BPA in water. Furthermore, during the treatment of real water samples (lake water and river water) with trace bisphenol pollutants, the complete removal of the pollutants were evidently observed, which strongly verified the possibility of CA-P-CDP for the practical application.

Radioactive cesium ion removal from wastewater using polymer metal oxide composites

Radioactive cesium ion (Cs-137) removal from wastewater was investigated by novel composite adsorbents, chitosan-bone powder (CS-KT) and chitosan-bone powder-iron oxide (CS-KT-M) at 25 and 50 °C. The characterization of adsorbents was performed by Fourier-Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller and Barrett-Joyner-Hallenda (BET-BJH), and Atomic Force Microscopy (AFM) analyses. While BET surface areas of CS-KT and CS-KT-M adsorbents were found to be 131.5 and 144.9 m²/g, respectively, average pore size and pore volume values were 4.69 nm/0.154 cm³/g and 7.49 nm/0.271 cm³/g, respectively. Amongst Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) models, Langmuir model fits well for Cs⁺ ion sorption by these adsorbents. The maximum adsorption capacity obtained from Langmuir adsorption isotherm was 0.98 × 10^-4 mol/g at 25 °C, and 1.16 × 10^-4 mol/g at 50 °C for CS-KT; it was found to be 1.79 × 10^-4 mol/g at 25 °C and 2.24 × 10^-4 mol/g at 50 °C for CS-KT-M. FT-IR analyses showed that Cs⁺ sorption occurs by its interaction with CO₃^2-, PO₄^3- and -NH₂ groups. The average adsorption energy "E" was calculated as ca.11 kJ/mol from D-R adsorption isotherm. The adsorption kinetics was interpreted well by pseudo-second order model.

Heavy metal ions' poisoning behavior-inspired etched UiO-66/CTS aerogel for Pb(II) and Cd(II) removal from aqueous and apple juice

Here, inspired by the poisoning process of heavy metal in human body that the accidental ingested heavy metal can anchor to the functional groups of DNA/protein/enzyme to exert their toxicities during the rapid blood circulation, we developed the adsorbent that enveloped Etched UiO-66 with abundant functional groups into chitosan (CTS) aerogel to capture Pb(II) and Cd(II) in aqueous and apple juice. SEM, XRD and FTIR spectra were used to characterize the Etched UiO-66/CTS aerogel. The results showed that Etched UiO-66/CTS aerogel has a three-dimensional porous structure, and -OH groups of CTS interact with Zr(IV) of Etched UiO-66 to form the stable UiO-66/CTS aerogel. Benefiting from the intrinsic properties of porous and abundant functional groups, Etched UiO-66/CTS aerogel exhibits satisfactory adsorption capacities of 654.9 mg g^-1 for Pb(II) and 343.9 mg g^-1 for Cd(II) at 45 °C. Moreover, the aerogel shows excellent removal efficiencies of 98.21% for Pb(II) and 98.70% for Cd(II) with initial concentration of 1.0 mg L^-1 in apple juice with little effect on the quality of apple juice. This strategy of mimetic heavy metal ions' poisoning behavior opens up a new avenue for the removal of heavy metal ions in complex matrices.

KOH-activated porous biochar with high specific surface area for adsorptive removal of chromium (VI) and naphthalene from water: Affecting factors, mechanisms and reusability exploration

Herein, a high-performance porous biochar described as PBC_KOH was successfully synthesized by two-step pyrolysis of corn straw with chemical activation of KOH, and was employed for the elimination of Cr(VI) and naphthalene (NAP) from water. Benefiting from KOH activation, the PBC_KOH was found to possess huge specific surface area of 2183.80 m²/g and many well-developed micropores with average particle size of 2.75 nm and main pore diameters distribution from 1 to 2 nm. The PBC_KOH presented an excellent adsorption performance with a theoretical monolayer uptake of 116.97 mg/g for Cr(VI) and a heterogeneous adsorption capacity of 450.43 mg/g for NAP. The uptake equilibrium was attained within about 120 min for Cr(VI), while about 180 min for NAP following avrami fractional-order model, revealing the existence of multiple kinetics during the adsorption. The thermodynamic results showed that the uptake of both Cr(VI) and NAP occurred spontaneously (-ΔG°), while in an endothermic nature for Cr(VI) (+ΔH°) and an exothermic characteristic for NAP (-ΔH°) with different randomness. Furthermore, the PBC_KOH was believed to enhance the Cr(VI) adsorption mainly through the combination of electrostatic attraction, complexation, ion exchange and reduction action, while achieving the high NAP uptake by pore filling and π-π stacking interactions.

Oil industry waste based non-magnetic and magnetic hydrochar to sequester potentially toxic post-transition metal ions from water

Solid waste conversion to value-added products is a stepping stone towards sustainable environment. Herein, sesame oil cake (SOC), an oil industry waste was utilized as a precursor to develop hydrochar (HC) samples by varying reaction temperature (150-250 °C) and time span (2-8 h), chemically treated with 10% H₂O₂ to optimize a sample with maximum yield and Pb(II) adsorption. Highest yield (29.2 %) and Pb(II) (24.57 mg/g at C_o: 15 mg/L) adsorption was observed on SOCHC@200 °C/6 h, magnetized (mSOCHC@200 °C/6 h) for comparative study. XRD displayed highly crystalline SOCHC@200 °C/6 h and amorphous mSOCHC@200 °C/6 h, both having a characteristic cellulose peak at 14.9°. mSOCHC@200 °C/6 h displayed superparamagnetic behavior with 11.2 emu/g saturation magnetization. IR spectra confirmed the development of samples rich in oxygen containing functionalities; an additional peak for iron oxides appeared at 586 cm^-1 in mSOCHC@200°C/6 h spectrum. Four major peaks at 531.9, 399.9, 348.2 and 284.7 eV, assigned to O 1s, N 1s, Ca 2p and C 1s, respectively were observed during XPS analyses. An additional peak at 710.3 eV, ascribed to Fe 2p was observed in mSOCHC@200C/6 h XPS spectrum, while a peak at 143.2 eV for Pb 4f appeared in spectra of both Pb(II) saturated samples. pH dependent (maximum at ∼6.7), exothermic Pb(II) adsorption was found. About 50-70% (at C_o: 25 mg/L) adsorption on both SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h was accomplished in a minute, attaining equilibrium in 180 and 240 min, respectively. Error functions and superimposed q_{e, exp}. and q_{e, cal.} values supported Langmuir isotherm model applicability, with respective q_m values of 304.9 and 361.7 mg/g at 25 °C for SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h. Kinetic data was fitted to PSO model. Highest (between 92.2 and 88.9 %) amount of Pb(II) from SOCHC@200 °C/6 h and mSOCHC@200 °C/6 h was eluted by 0.01 M HCl.

Single-step pyrolysis for producing magnetic activated carbon from tucumã (Astrocaryum aculeatum) seed and nickel(II) chloride and zinc(II) chloride. Application for removal of nicotinamide and propanolol

The present research describes the synthesis of new nanomagnetic activated carbon material with high magnetization, and high surface area prepared in a single pyrolysis step that is used for the carbonization, activation, and magnetization of the produced material. The pyrolysis step of tucumã seed was carried out in a conventional tubular oven at 600 °C under N₂-flow. It was prepared three magnetic carbons MT-1.5, MT-2.0, MT-2.5, that corresponds to the proportion of biomass: ZnCl₂ always 1:1 and varying the proportion of NiCl₂ of 1.5, 2.0, and 2.5, respectively. These magnetic nanocomposites were characterized by Vibrating Sample Magnetometer (VSM), X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, hydrophobic/hydrophilic balance, CHN/O elemental analysis, modified Boehm titration, N₂ adsorption-desorption isotherms; and pH_pzc. All the materials obtained presented Ni particles with an average crystallite size of less than 33 nm. The MT-2.0 was employed for the removal of nicotinamide and propranolol from aqueous solutions. Based on Liu isotherm, the Q_max was 199.3 and 335.4 mg g^-1 for nicotinamide and propranolol, respectively. MT-2.0 was used to treat simulated pharmaceutical industry effluents attaining removal of all organic compounds attaining up to 99.1 % of removal.

Evaluation of adsorptive desulfurization performance and economic applicability comparison of activated carbons prepared from various carbon sources

Adsorptive desulfurization (ADS) using activated carbon (AC) as adsorbent presents competitive potential in separating thiophenic sulfur from liquid fuels with high selectivity under mild operation conditions. It is also a highly economic remedy in ultra-low sulfur content situations. Most importantly, a suitable feedstock for macroscopic quantity preparation of AC adsorbents with good adsorptive desulfurization performance and low-cost is required to satisfy the requirements of this field. In this work, four representative substances (i.e., coal, coconut shell, polyurethane plastic waste, and petroleum coke) were selected as the carbon source for the preparation of various AC adsorbents. The physicochemical properties of the prepared AC adsorbents were characterized using BET, SEM, XRD, XPS, elemental analysis and Boehm's method. The corresponding adsorptive desulfurization performance was investigated. The corresponding desulfurization capacity obtained was in the order: CS-ACA > PUPW-ACA > PC-ACA > AT-ACA. Under the optimal conditions of 30 °C and 30 min contact time, the desulfurization rate of 0.5 g PUPW-ACA can reach about 98%. The HHV of non-condensable gas generated during the experiment was calculated, and the HHV of the pyrolysis oil was measured. The results showed that the by-products produced by PC had the highest HHV. The economics of the desulfurization of the four kinds of activated carbon were analyzed and evaluated. From a comprehensive analysis, PUPW-ACA has the highest economic production value and has the potential for industrial production. This plays a dual role in environmental protection.

Selection and preparation method of a low-cost, environmentally-friendly desulfurization adsorbent raw material.

Using basic parameters to evaluate adsorption potential of alternative materials: example of amoxicillin adsorption by activated carbon produced from termite bio-waste

The minimum set of parameters that can be used to assess the adsorption capacity of activated carbon (AC) produced from termite bio-waste was determined. Three types of AC were prepared: AC600 at 600 °C, MAC600 at the same temperature and impregnated with FeCl₃, and AC800 at 800 °C. The influence of the solution pH on the adsorption, adsorption kinetics, isotherms and thermodynamic parameters was considered to characterize the amoxicillin (AMX) adsorption process. The AC materials had surface areas (m² g^-1) of approximately 248.8 for AC600, 501.6 for AC800 and 269.5 for MAC600, with point of zero charge (pH_PZC) values of 8.3, 7.5 and 1.7, respectively. A time period of 30 min was chosen for the adsorption kinetics, which was best represented by the pseudo-first-order model for AC600, the intraparticle diffusion model for AC800 and the pseudo-second-order model for MAC600. Regarding the isotherms, a maximum adsorption of 23.4 mg g^-1 was found for AC800. In general, the thermodynamic parameters demonstrated a non-spontaneous process. It seems that the medium conditions, the adsorbate and adsorbent characteristics, and the Gibbs free energy are the most important parameters to be considered in a preliminary assessment of the adsorption efficiency of specific adsorbent/adsorbate pairs.

Activated hydrochar produced from brewer's spent grain and its application in the removal of acetaminophen

Acetaminophen has shown a gradual increase in detection in surface waters. Although present in low concentrations, it should be removed to prevent deleterious effects. Thus, adsorption onto activated carbon is emphasized. Adsorbents may be produced by hydrothermal carbonization (HTC), an environmental-friendly process. Therefore, this work aimed to investigate the use of HTC, verifying its application in acetaminophen removal. Brewer's spent grain (BSG), its hydrochar (HC-BSG) and its activated hydrochar (AHC-BSG) were characterized. HTC provided material with high carbon content. Lignocellulosic breakdown has been demonstrated in HC-BSG and AHC-BSG, but in the latter it was more intense as a result of activation with KOH. Also, a high surface area was found in AHC-BSG (1512.83 m² g^-1), resulting in an adsorption of 318.00 mg g^-1. The pseudo-second-order and Langmuir models were fitted to the experimental data. Therefore, HTC was effective as a pretreatment for AHC-BSG, resulting in significant acetaminophen removals.

Sustainable Biomass Activated Carbons as Electrodes for Battery and Supercapacitors-A Mini-Review

Some recent developments in the preparation of biomass carbon electrodes (CEs) using various biomass residues for application in energy storage devices, such as batteries and supercapacitors, are presented in this work. The application of biomass residues as the primary precursor for the production of CEs has been increasing over the last years due to it being a renewable source with comparably low processing cost, providing prerequisites for a process that is economically and technically sustainable. Electrochemical energy storage technology is key to the sustainable development of autonomous and wearable electronic devices. This article highlights the application of various types of biomass in the production of CEs by using different types of pyrolysis and experimental conditions and denotes some possible effects on their final characteristics. An overview is provided on the use of different biomass types for the synthesis of CEs with efficient electrochemical properties for batteries and supercapacitors. This review showed that, from different biomass residues, it is possible to obtain CEs with different electrochemical properties and that they can be successfully applied in high-performance batteries and supercapacitors. As the research and development of producing CEs still faces a gap by linking the type and composition of biomass residues with the carbon electrodes' electrochemical performances in supercapacitor and battery applications, this work tries to diminish this gap. Physical and chemical characteristics of the CEs, such as porosity, chemical composition, and surface functionalities, are reflected in the electrochemical performances. It is expected that this review not only provides the reader with a good overview of using various biomass residues in the energy storage applications, but also highlights some goals and challenges remaining in the future research and development of this topic.

Engineering magnetic N-doped porous carbon with super-high ciprofloxacin adsorption capacity and wide pH adaptability

We report a high performance magnetic N-doped nanoporous carbon (MNPC) adsorbent synthesized by a simple single-step pyrolysis protocol. Grinding the mixture of ZnO nanoparticles, cobalt hydroxide and 2-methylimidazole produced Zn/Co-ZIFs that were converted into MNPC following subsequent pyrolysis in N₂ atmosphere. The optimized MNPC-700-0.4 adsorbent, obtained at 700 °C with Co/(Zn + Co) molar ratio of 0.4, is featured with super-high ciprofloxacin (CIP) adsorption capacity of 1563.7 mg g^-1 at 25 °C, fast adsorption dynamics (1.5 h of adsorption equilibrium time), wide pH adaptability (almost unchanged CIP adsorption capacity in pH 4-10), and good magnetic property. The magnetic property and CIP adsorption performance can be easily regulated by modulating the molar ratio of Co/(Zn + Co) and the pyrolysis temperature. The optimal MNPC-700-0.4 was chosen to explore adsorption kinetics and isotherm. The effects of pH, ionic strength and humic acid on CIP adsorption were investigated. CIP adsorption obeyed pseudo-second-order kinetics and well fitted the Langmuir adsorption model. The favorable textural properties (high surface area and pore volume), riched nitrogen structure and large amounts of defects endow the MNPC-700-0.4 lots of sites for CIP adsorption. The CIP adsorption onto MNPC-700-0.4 was mainly controlled by the electrostatic interaction, hydrophobic interaction, π-π stacking and hydrogen bond.