A comparative study of chemical treatment by MgCl2, ZnSO4, ZnCl2, and KOH on physicochemical properties and acetaminophen adsorption performance of biobased porous materials from tree bark residues

Synthesis and characterization of a novel TiO2@chitosan/alginate nanocomposite sponge for highly efficient removal of As(V) ions from aqueous solutions: Adsorption isotherm, kinetics, experiment and adsorption mechanism optimization using Box-Behnken design

This research uses a novel TiO2@CSC.Alg composite sponge was created by encasing TiO2 nanoparticles in the natural polymers alginate and chitosan, resulting in a nanocomposite that is both ecologically friendly and biocompatible. Using the generated nanocomposite as a new environmentally friendly adsorbent, As(V) heavy metal ions were effectively removed from aqueous media. The following techniques were used to analyse the physicochemical properties of the obtained materials: pHZPC, FTIR, XRD, BET, SEM, and XPS. Utilizing nitrogen adsorption/desorption isotherms, the TiO2@CSC.Alg composite sponge's textural properties were identified. This revealed a BET surface area of 168.42 m2/g and a total pore volume of 1.18 cc/g, indicating its porous nature and potential for high adsorption capacity. Examine the effects of temperature, pH, dose, and beginning concentration on adsorption. The adsorption characteristics were determined based on equilibrium and adsorption kinetics measurements. The adsorption process was both pseudo-second-order (PSOE) and Langmuir isothermally fit. Chemisorption was the adsorption method since the adsorption energy was 25.45 kJ·mol-1. An endothermic and spontaneous adsorption process was indicated by more metal being absorbed as the temperature increased. The optimal conditions for adsorption were optimized via Box-Behnken design software to be pH of 5 in the solution, a dosage of 0.02 g of the TiO2@CSC.Alg composite sponge per 25 mL, and an arsenate (As(V)) solution the adsorption capacity was 202.27 mg/g are ideal for efficient adsorption. These parameters are critical in achieving the maximum adsorption capacity of the composite sponge for arsenate, which could be beneficial for water purification applications. Utilizing Design-Expert software's response surface methodology (RSM) and Box-Behnken design (BBD), the adsorption process was optimized with the fewest planned tests. After six successive cycles of adsorption and desorption, the adsorbent stability was confirmed by the adsorbent reusability test without any noticeable decrease in removal efficacy. Additionally, it displayed good efficiency, the same XRD and XPS data before and after reuse, and no change in chemical composition.

Synthesis of sustainable mesoporous sulfur-doped biobased carbon with superior performance sodium diclofenac removal: Kinetic, equilibrium, thermodynamic and mechanism

Over the last years, the strategy of employing inevitable organic waste and residue streams to produce valuable and greener materials for a wide range of applications has been proven an efficient and suitable approach. In this research, sulfur-doped porous biochar was produced through a single-step pyrolysis of birch waste tree in the presence of zinc chloride as chemical activator. The sulfur doping process led to a remarkable impact on the biochar structure. Moreover, it was shown that sulfur doping also had an important impact on sodium diclofenac (S-DCF) removal from aqueous solutions due to the introduction of S-functionalities on biochar surface. The adsorption experiments suggested that General and Liu models offered the best fit for the kinetic and equilibrium studies, respectively. The results showed that the kinetic was faster for the S-doped biochar while the maximum adsorption capacity values at 318 K were 564 mg g-1 (non-doped) and 693 mg g-1 (S-doped); highlighting the better affinity of S-doped biochar for the S-DCF molecule compared to non-doped biochar. The thermodynamic parameters (ΔH0, ΔS0, ΔG0) suggested that the S-DCF removal on both adsorbents was spontaneous, favourable, and endothermic.

Promoting the circular economy: Valorization of a residue from industrial char to activated carbon with potential environmental applications as adsorbents

Pyrolysis of residues enriched with carbon, such as in agroforestry or industrial activities, has been postulated as an emerging technology to promote the production of biofuels, contributing to the circular economy and minimizing waste. However, during the pyrolysis processes a solid fraction residue is generated. This work aims to study the viability of these chars to develop porous carbonaceous materials that can be used for environmental applications. Diverse chars discharged by an industrial pyrolysis factory have been activated with KOH. Concretely, the char residues came from the pyrolysis of olive stone, pine, and acacia splinters, spent residues fuel, and cellulose artificial casings. The changes in the textural, structural, and composition characteristics after the activation process were studied by N2 adsorption-desorption isotherms, scanning electron microscopy, FTIR, elemental analysis, and XPS. A great porosity was developed, SBET within 776-1186 m2 g-1 and pore volume of 0.37-0.59 cm3 g-1 with 70-90% of micropores contribution. The activated chars were used for the adsorption of CO2, leading to CO2 maximum uptakes of 90-130 mg g-1. There was a good correlation between the CO2 uptake with microporosity and oxygenated surface groups of the activated chars. Moreover, their ability to adsorption of contaminants in aqueous solution was also evaluated. Concretely, there was studied the adsorption of aqueous heavy metals, i.e., Cd, Cu, Ni, Pb, and Zn, and organic pollutants of emerging concern such as caffeine, diclofenac, and acetaminophen.

Comparison of modeling, optimization, and prediction of important parameters in the adsorption of cefixime onto sol-gel derived carbon aerogel and modified with nickel using ANN, RSM, GA, and SOLVER methods

Today, the main goal of many researchers is the use of high-performance, economically and industrially justified materials, as well as recyclable materials in removing organic and dangerous pollutants. For this purpose, sol-gel derived carbon aerogel modified with nickel (SGCAN) was used to remove Cefixime from aqueous solutions. The influence of important parameters in the cefixime adsorption onto SGCAN was modeled and optimized using artificial neural network (ANN), response surface methodology (RSM), genetic algorithm (GA), and SOLVER methods. R software was applied for this purpose. The design range of the runs for a time was in the range of 5 min-70 min, concentration in the range of 5 mg L-1 to 40 mg L-1, amount of adsorbent in the range of 0.05 g L-1 to 0.15 g L-1, and pH in the range of 2.0-11. The results showed that the ANN model due to lower Mean Squared Error (MSE), Sum of Squared Errors (SSE), and Root Mean Squared Error (RMSE) values and also higher R2 is a superior model than RSM. Also, due to the superiority of ANN over the RSM model, the optimum results were calculated based on GA. Based on GA, the highest Cefixime adsorption onto SGCAN was obtained in pH, 5.98; reaction time, 58.15 min; initial Cefixime concentration, 15.26 mg L-1; and adsorbent dosage, 0.11 g L-1. The maximum adsorption capacity of Cefixime onto SGCAN was determined to be 52 mg g-1. It was found the pseudo-second-order model has a better fit with the presented data.

Integral evaluation of effective conversion of sewage sludge from WWTP into highly porous activated carbon

Urban sewage sludge (SL) is a major concern due to the number of environmental problems it causes. Its application for different purposes is strictly regulated, limiting the possibilities of recycling and reusing this material. Thus, in this work, a complete study of a simple method to convert SL into activated carbon (AC) was carried out. The comprehensive study involves an evaluation of the main process parameters, such as the activating agent (AA) content (25 %, 33 %, 50 %), using the lowest amount of AA as novelty, different pyrolysis temperatures (600 and 800 °C), and purification conditions (6 M HCl:AC ratio, v:w). Under controlled and optimised conditions and through a single combined activation and pyrolysis step followed by acid purification, ACs with well-developed porosity can be obtained. Surface area values of around 870 m2/g and over 60 % carbon content were achieved, demonstrating that the prepared ACs could have applications in a wide variety of fields as high-value products. As an innovative aspect in this research, the gases streams and liquid effluents generated during the global process were analysed, achieving elimination of over 63 % of the concentration of the chemical elements contained in the SL during the chemical purification stage. Finally, mass, energy, and economic balances were carried out to estimate the production cost of AC derived from SL (<€ 8/kg AC).

Doping matters in carbon nanomaterial efficiency in environmental remediation

Carbon nanomaterials (CNMs) are rapidly emerging in materials science research due to their widespread environmental applications. They are useful for environmental pollutants' remediation through various methods. Heteroatom doping resulted in reliable approaches to overcome pristine CNMs challenges. The engineering of the dopants is believed to be a promising route to improve the efficiency of CNMs in environmental remediation. The idea of doping has been attractive since it allows the control of electronic properties due to the electron transfer between dopants and the host material and the dopants along with the bonding between analogous atoms and carbon atoms. This mini-review, through computational and experimental studies, puts special emphasis on the role of doping different CNMs as an efficient approach to enhance the environmental remediation.

Competitive adsorption of acetaminophen and caffeine onto activated Tingui biochar: characterization, modeling, and mechanisms

Tingui biochar (TB) activated with potassium hydroxide (TB-KOH) was synthesized in the present study. The adsorption capacity of TB-KOH was evaluated for the removal of acetaminophen and caffeine in monocomponent and bicomponent solutions. As a result, the study of the TB-KOH characterization as well as the adsorption kinetics, isotherm, thermodynamics, and a suggestion of the global adsorption mechanism are presented. TB-KOH was characterized through physical-chemical analysis to understand its surface morphology and how it contributes to the adsorption of these drugs. Furthermore, modelling using advanced statistical physical models was performed to describe how acetaminophen and caffeine molecules are adsorbed in the active sites of TB-KOH. Through the characterizations, it was observed that the activation with KOH contributed to the development of porosity and functional groups (-OH, C-O, and C = O) on the surface of TB. The monocomponent adsorption equilibrium was reached in 90 min with a maximum adsorption capacity of 424.7 and 350.8 mg g-1 for acetaminophen and caffeine, respectively. For the bicomponent solution adsorption, the maximum adsorption capacity was 199.4 and 297.5 mg g-1 for acetaminophen and caffeine, respectively. The isotherm data was best fitted to the Sips model, and the thermodynamic study indicated that acetaminophen removal was endothermic, while caffeine removal was exothermic. The mechanism of adsorption of acetaminophen and caffeine by TB-KOH was described by the involvement of hydrogen bonds and π-π interactions between the surface of TB-KOH and the molecules of the contaminants.

Selective adsorption of tetracycline and copper(II) on ion-imprinted porous alginate microspheres: performance and potential mechanisms

A novel epichlorohydrin and thiourea grafted porous alginate adsorbent (UA-Ca/IIP) was synthesized using ion-imprinting and direct templating to remove copper ions (Cu(II)) and tetracycline (TC) in aqueous solution. UA-Ca/IIP demonstrated great selectivity for Cu(II) and TC among different coexisting anions (CO32-, PO43- and SO42-), cations (Ca2+, Mg2+ and NH4+), and antibiotics (oxytetracycline and sulfamethoxazole). The adsorption of TC and Cu(II) by UA-Ca/IIP was significantly affected by the pH of the solution, and the quantity of TC and Cu(II) adsorbed reached a maximum at pH 5. A pseudo-second-order model better fitted the kinetic data; the Langmuir model predicted the maximum adsorption quantities 3.527 mmol TC g-1 and 4.478 mmol Cu(II) g-1 at 298 K. Thermodynamic studies indicated that the TC and Cu(II) adsorption was more rapid at a higher temperature. Antagonistic and synergistic adsorption experiments showed that the adsorption capacity of TC would increase significantly with the increase of Cu(II) concentration. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated that along with the influence of pH, electrostatic interaction and complexation were the main mechanisms of TC and Cu(II) adsorption. Regeneration experiments revealed that TC and Cu(II) were removed efficiently and that UA-Ca/IIP was recyclable over the long term. These results show that the modified porous alginate microsphere is a green and recyclable adsorbent, which has good selectivity and high adsorption performance for the removal of TC and Cu(II).

Ultrasonically assisted hydrothermal synthesis of tungsten(VI) oxide-TiO2 nanocomposites for enhanced photocatalytic degradation of non-narcotic drug paracetamol under natural solar light: insights into degradation pathway, mechanism, and toxicity assessment

Photocatalytic degradation of pharmaceutical residues through natural solar radiation represents a green and economical treatment process. In this work, ultrasonically assisted hydrothermal synthesis of WO3-TiO2 nanocomposite was carried out at 140-150 °C for 5 h and calcinated at 600 °C. The structural and optical properties of the synthesized material were investigated using techniques like XRD, FESEM/EDX, HRTEM, BET surface area, UV-DRS optical analysis, and photocurrent response. The band gap of TiO2 was successfully reduced from 3.0 to 2.54 eV and thus making it effective under solar light. Complete degradation of paracetamol (50 ppm and natural pH of 6.5) was achieved in 3.5 h under natural sunlight at catalyst dose of 0.5 g/l. The extent of mineralization was evaluated by measuring the COD reduction. Based on the degradation products identified by GC-MS/LC-TOF-MS, the degradation process under natural solar-light could be interpreted to initiate through OH. radical species. The toxicity removal of the treated paracetamol solution under natural solar-light was evaluated by the seed germination test using Spinacia oleracea seeds and exhibited 66.70% seed germination, confirming the reduction in toxicity. The enhanced photocatalytic efficiency of the nanocomposite is attributed to the higher surface area, low rutile content, lower band gap, and incorporation of WO3, which led to an extended absorption range and a slower rate of electron-hole recombination. The technical insights presented in this research offer a feasible approach for utilizing natural solar light driven photocatalysis for wastewater treatment in an efficient and sustainable way. The proposed degradation pathway, and seed germination test (toxicity removal) of the treated paracetamol solution under natural sunlight, has not been previously evaluated.

Ivermectin adsorption by commercial charcoal in batch and fixed-bed operations

Emerging contaminants were used during the COVID-19 pandemic, including ivermectin. Studies that limit the optimal adsorption parameters of ivermectin are scarce in the literature. In this study, we analyzed the adsorption of ivermectin with a high surface area and porosity charcoal. Isotherms were better fitted to the Koble-Corrigan model. The maximum capacity was 203 μg g-1 at 328 K. Thermodynamics indicated a spontaneous and endothermic behavior. The equilibrium was quickly reached within the first few minutes regardless of the ivermectin concentration. The linear driving force (LDF) model fitted the kinetic data (qexp = 164.8 μg g-1; qpred = 148.1 μg g-1) at 100 μg L-1 of ivermectin. The model coefficient (KLDF) and diffusivity (Ds) increased with increasing drug concentration. Two sloped curves were obtained in the column experiments, with a breakthrough time of 415 min and 970 min. The capacity of the column (qeq) was 76 μg g-1. The length of the mass transfer zone was 9.04 and 14.13 cm. Therefore, it can be concluded that the adsorption of ivermectin is highly sensitive to changes in pH, being favored in conditions close to neutrality. Commercial activated charcoal was highly efficient in removing the studied compound showing high affinity with very fast kinetics and a good performance in continuous operation mode.

Efficient Removal of Analgesic and Anti-Inflammatory Drugs from Sewage Treatment Plant Effluents Using Magnetite Nanoparticles Synthesized Red Mud

Due to the COVID-19 epidemic, the consumption of pharmaceuticals, especially paracetamol, has sharply increased on a global scale. The increasing concentration of analgesic and anti-inflammatory drugs (AAIDs) in the aquatic medium is a global problem for human and aquatic life. Therefore, simple and effective treatment options for removing AAIDs from wastewater after the COVID-19 pandemic are needed. The removal of AAIDs (acetaminophen, acetylsalicylic acid, codeine, diclofenac, ibuprofen, indomethacin, ketoprofen, mefenamic acid, naproxen, and phenylbutazone) from sewage treatment plant (STP) effluents by the prepared magnetite nanoparticles synthesized from red mud (mNPs-RM) is presented for the first time in this study. The removal efficiencies of AAIDs onto mNPs-RM were determined to be between 90% (diclofenac) and 100% (naproxen, codeine, and indomethacin). Acetaminophen (paracetamol) was used as a model compound in kinetic and isotherm model studies. The adsorption of acetaminophen was matched well with the pseudo second order kinetic model. Film diffusion governed its rate mechanism. The Freundlich isotherm model preferably fitted the adsorption data with an adsorption capacity of 370 mg/g at 120 min contact time at pH 7.0 at 25 °C. Furthermore, the regenerated mNPs-RM were used four times without affecting the adsorption capacity and the magnetic separability. mNPs-RM can be used as a simple, inexpensive and effective adsorbent for removing AAIDs from STP effluents. Also, low cost adsorbent obtained from industrial waste could be employed to replace the high cost activated carbons for the adsorption of other micro pollutants in STP effluents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11270-023-06404-7.

Adsorption of Omeprazole on Biobased Adsorbents Doped with Si/Mg: Kinetic, Equilibrium, and Thermodynamic Studies

This paper proposes an easy and sustainable method to prepare high-sorption capacity biobased adsorbents from wood waste. A biomass wood waste (spruce bark) was employed to fabricate a composite doped with Si and Mg and applied to adsorb an emerging contaminant (Omeprezole) from aqueous solutions, as well as synthetic effluents loaded with several emerging contaminants. The effects of Si and Mg doping on the biobased material's physicochemical properties and adsorptive performance were evaluated. Si and Mg did not influence the specific surface area values but impacted the presence of the higher number of mesopores. The kinetic and equilibrium data presented the best fitness by the Avrami Fractional order (AFO) and Liu isotherm models, respectively. The values of Q_max ranged from 72.70 to 110.2 mg g^-1 (BP) and from 107.6 to 249.0 mg g^-1 (BTM). The kinetic was faster for Si/Mg-doped carbon adsorbent, possibly due to different chemical features provoked by the doping process. The thermodynamic data showed that the adsorption of OME on biobased adsorbents was spontaneous and favorable at four studied temperatures (283, 293, 298, 303, 308, 313, and 318 K), with the magnitude of the adsorption correspondent to a physical adsorption process (ΔH° < 2 kJ mol^-1). The adsorbents were applied to treat synthetic hospital effluents and exhibited a high percentage of removal (up to 62%). The results of this work show that the composite between spruce bark biomass and Si/Mg was an efficient adsorbent for OME removal. Therefore, this study can help open new strategies for developing sustainable and effective adsorbents to tackle water pollution.

A novel calcium peroxide/attapulgite-Fe(II) process for high concentration phosphate removal and recovery: Efficiency and mechanism

Phosphorus (P) has been overused in livestock farming, which inevitably results in high-concentration P-containing wastewater. Managing total phosphorus discharge is important to prevent eutrophication in aquatic environments, thus it is critical to develop new technologies for the removal and recovery of high-concentration phosphate. In this study, a novel calcium peroxide/attapulgite (CP/ATP) composite was developed and coupled with Fe(II) for high-concentration phosphate removal and recovery. The results demonstrated that the optimal dosage of the CP/ATP-Fe(II) process was CP/ATP = 0.25 g/L and Fe(II) = 2 mM. The pH effect on phosphate removal was minimal, while phosphate removal efficiency rose by 16.7% with the temperature increased from 10 °C to 25 °C. The co-existing ions exhibited little effect on phosphate removal, and the CP/ATP-Fe(II) process showed effective phosphate removal from the real piggery wastewater. The P content of the precipitates after phosphate removal by this process was as high as 25.82%, indicating its good potential for P recycling. A significant synergistic effect existed in CP/ATP and Fe(II) for phosphate removal, and the SEM-EDS, XRD, Raman and XPS characterization exhibited that the phosphate removal mainly relied on the in-situ-formed Fe(III) and the participation of calcium (Ca) species. Co-precipitation was the predominant mechanism for phosphate removal, and the proportions of Fe(III)-P, Ca-P and Ca-Fe(III)-P in the precipitates were 51.5%, 31.2% and 17.3%, respectively. This study provides a highly efficient process for phosphate removal and recovery from wastewater, and insights into interactions among phosphorus, iron and calcium.

Effective removal of selected pharmaceuticals from sewerage treatment plant effluent using natural clay (Na-montmorillonite)

The consumption of pharmaceuticals has rapidly increased on a global scale due to the serious increase in Covid-19, influenza and respiratuar sinsityal virus, which is called "triple epidemic" in the world. The use of non-prescription analgesic and anti-inflammatory drugs (AAIDs), especially paracetamol, is higher compared to pre-pandemic. This increased the AAIDs load discharged to the aqueous media through sewerage treatment plant (STP). Therefore, simple and effective treatment options for removing AAIDs from STP effluents are needed. The aim of the study was to remove AAIDs (paracetamol, acetylsalicylic acid, codeine, diclofenac, ibuprofen, indomethacin, ketoprofen, mefenamic acid, naproxen, and phenylbutazone) from STP effluents by nearly pure natural clay Na-montmorillonite. The Na-montmorillonite taken from the Ordu region in the northern part of Turkey. Surface area of the Na-montmorillonite is 99.58 m2/g and CEC is 92.40 meq/100 g. The removal efficiencies of AAIDs using Na-montmorillonite were between 82 ± 5% (ibuprofen) and 94 ± 4% (naproxen). Paracetamol was used as a model compound in kinetic and isotherm model studies. Freundlich isotherm model and the pseudo second order kinetic model were the best-fit using the obtained experimental data. Film diffusion governed its rate mechanism. The paracetamol adsorption capacity was acquired as 244 mg/g at 120 min contact time at pH 6.5 at 25 °C. With this study, it could be shown that montmorillonite can be used effectively to eliminate paracetamol from STP effluent. Natural clay can be used as a simple, inexpensive and effective adsorbent for removing AAIDs from STP effluents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13201-023-01930-5.

Wood waste-based functionalized natural hydrochar for the effective removal of Ce(III) ions from aqueous solution

In this study, a sustainable and easily prepared hydrochar from wood waste was studied to adsorb and recover the rare earth element cerium (Ce(III)) from an aqueous solution. The results revealed that the hydrochar contains several surface functional groups (e.g., C-O, C = O, OH, COOH), which largely influenced its adsorption capacity. The effect of pH strongly influenced the Ce(III) removal, achieving its maximum removal efficiency at pH 6.0 and very low adsorption capacity under an acidic solution. The hydrochar proved to be highly efficient in Ce(III) adsorption reaching a maximum adsorption capacity of 327.9 mg g^-1 at 298 K. The kinetic and equilibrium process were better fitted by the general order and Liu isotherm model, respectively. Possible mechanisms of Ce(III) adsorption on the hydrochar structure could be explained by electrostatic interactions and chelation between surface functional groups and the Ce(III). Furthermore, the hydrochar exhibited an excellent regeneration capacity upon using 1 mol L^-1 of sulfuric acid (H₂SO₄) as eluent, and it was reused for three cycles without losing its adsorption performance. This research proposes a sustainable approach for developing an efficient adsorbent with excellent physicochemical and adsorption properties for Ce(III) removal.

Adsorption mechanism of phosphorus on biomass ash modified with lanthanum immobilized by chitosan

The immobilized lanthanum-modified biomass ash gel ball (CS-La-BA) was prepared with lanthanum chloride, biomass ash, and chitosan to remove phosphorus from water. CS-La-BA was characterized by several analytical techniques. SEM-EDS results showed that CS-La-BA has a well-developed pore structure and abundant adsorption sites. The surface area of BET is 75.46 m²/g and the pore size is mostly at 1.84 nm, indicating that it is a composite porous material with abundant microporous structure. The presence of La on biomass ash and the charge property of CS-La-BA were determined by XRD and zeta potential, and the adsorption mechanism of CS-La-BA on phosphate, including precipitation, electrostatic adsorption, ligand exchange, and complexation mechanism, was revealed by FTIR and XPS. The effects of pH, temperature, adsorbent dosage, initial phosphorus concentration, adsorption time, and coexisting ions on the phosphorus uptake performance of CS-La-BA were discussed. The adsorption experiment results show that the phosphorus removal rate of CS-La-BA can reach 95.6%. Even after six desorption and regeneration experiments, the phosphorus removal rate still reaches 68.13%, which indicates that CS-La-BA has good phosphorus adsorption performance and desorption and regeneration capacity. The phosphorus adsorption process of CS-La-BA conforms to the Freundlich isotherm adsorption equation and general-order kinetic model. The internal diffusion of the adsorption process is dominant, and the maximum adsorption capacity is 31.73 mg/g (25 ℃). Thermodynamic experiments show that the adsorption process of phosphorus by CS-La-BA is a spontaneous entropy increase process.

Euterpe oleracea-based biochar for clonazepam adsorption: synthesis, characterization, adsorption properties, and toxicity assays

The consumption of açaí fruit (Euterpe oleracea) has largely increased worldwide, resulting in a significant increase in the demand for its pulp. As a result, the small producing communities end up with large amounts of açaí endocarp residues, creating local environmental pollution problems. Therefore, chemical and physical routes were investigated for producing açaí endocarp adsorbents to propose a locally viable solution for this problem. The adsorption properties of the produced biochars were tested for clonazepam (CZM) removal, and the toxicity of the final solutions was evaluated. The results revealed that the chemical route generated biochar with about twice the surface area and pore volume (762 m² g^-1 and 0.098 cm³ g^-1) than the physical route (498 m² g^-1 and 0.048 cm³ g^-1). Furthermore, the Sips isotherm better described the CZM adsorption equilibrium for both biochars, with q_s values of 26.94 and 61.86 mg g^-1 for the physical- and chemical-activated adsorbents. Moreover, recycling studies were performed, and the chemical-activated biochar was stable for up to three cycles, reaching removal rates superior to 80%. Besides, the final toxicity decreased after the adsorptive treatment. Therefore, chemical activation can be used as a simple and effective method for producing stable and compelling adsorbents as an elegant way of adding value to the residues from açaí production, helping solve local environmental problems.

Nitrogen Doped Porous Biochar/β-CD-MOFs Heterostructures: Bi-Functional Material for Highly Sensitive Electrochemical Detection and Removal of Acetaminophen

Acetaminophen (AC) is one of the most common over-the-counter drugs, and its pollutant in groundwater has attracted more attention due to its serious risk to human health. Currently, the research on AC is mainly focused on its detection, but few are concerned about its removal. In this work, for the first time, nitrogen-doped Soulangeana sepals derived biochar/β-cyclodextrin-Metal-organic frameworks (N-SC/β-CD-MOFs) composite was proposed for the simultaneous efficient removal and detection of AC. N-SC/β-CD-MOFs combined the properties of host-guest recognition of β-CD-MOFs and porous structure, high porosity, and large surface area of N-SC. Their synergies endowed N-SC/β-CD-MOFs with a high adsorption capacity toward AC, which was up to 66.43 mg/g. The adsorption type of AC on the surface of N-SC/β-CD-MOFs conformed to the Langmuir adsorption model, and the study of the adsorption mechanism showed that AC adsorption on N-SC was mainly achieved through hydrogen bonding. In addition, the high conductivity, large specific surface area and abundant active sites of N-SC/β-CD-MOFs were of great significance to the high-performance detection of AC. Accordingly, the sensor prepared with N-SC/β-CD-MOFs presented a wide linear range (1.0-30.0 μM) and a low limit of detection of 0.3 nM (S/N = 3). These excellent performances demonstrate that N-SC/β-CD-MOFs could act as an efficient dual-functional material for the detection and removal of AC.

Sustainable Biomass-Derived Carbon Electrodes for Potassium and Aluminum Batteries: Conceptualizing the Key Parameters for Improved Performance

The development of sustainable, safe, low-cost, high energy and density power-density energy storage devices is most needed to electrify our modern needs to reach a carbon-neutral society by ~2050. Batteries are the backbones of future sustainable energy sources for both stationary off-grid and mobile plug-in electric vehicle applications. Biomass-derived carbon materials are extensively researched as efficient and sustainable electrode/anode candidates for lithium/sodium-ion chemistries due to their well-developed tailored textures (closed pores and defects) and large microcrystalline interlayer spacing and therefore opens-up their potential applications in sustainable potassium and aluminum batteries. The main purpose of this perspective is to brief the use of biomass residues for the preparation of carbon electrodes for potassium and aluminum batteries annexed to the biomass-derived carbon physicochemical structures and their aligned electrochemical properties. In addition, we presented an outlook as well as some challenges faced in this promising area of research. We believe that this review enlightens the readers with useful insights and a reasonable understanding of issues and challenges faced in the preparation, physicochemical properties and application of biomass-derived carbon materials as anodes and cathode candidates for potassium and aluminum batteries, respectively. In addition, this review can further help material scientists to seek out novel electrode materials from different types of biomasses, which opens up new avenues in the fabrication/development of next-generation sustainable and high-energy density batteries.

Cellulose Fiber Rejects as Raw Material for Integrated Production of Pleurotus spp. Mushrooms and Activated Biochar for Removal of Emerging Pollutants from Aqueous Media

Cellulose fiber rejects from industrial-scale recycling of waste papers were dried and de-ashed using a combined cyclone-drying and sieving process. The upgraded fiber reject was used as a component of substrates for the cultivation of Pleurotus ostreatus and Pleurotus eryngii mushrooms. Acetic acid (AA) and acid whey (AW) were used to adjust the pH of fiber reject-based substrates. Spent substrate (SMS) was used for the production of activated biochar using H₃PO₄ and KOH as activating agents and pyrolysis temperatures of 500, 600, and 700 °C. The effectiveness of the biochars in removing pollutants from water was determined using acetaminophen and amoxicillin. By using a feeding rate of 250 kg/h and a drying air temperature of 70 °C, the moisture content of the raw fiber rejects (57.8 wt %) was reduced to 5.4 wt %, and the ash content (39.2 wt %) was reduced to 21.5 wt %. Substrates with 60 and 80 wt % de-ashed cellulose fiber were colonized faster than a birch wood-based control substrate. The adjustment of the pH of these two substrates to approximately 6.5 by using AA led to longer colonization times but biological efficiencies (BEs) that were higher or comparable to that of the control substrate. The contents of ash, crude fiber, crude fat, and crude protein of fruit bodies grown on fiber reject-based substrates were comparable to that of those grown on control substrates, and the contents of toxic heavy metals, that is, As, Pb, Cd, and Hg, were well below the up-limit values for food products set in EC regulations. Activated biochar produced from fiber reject-based SMS at a temperature of 700 °C resulted in a surface area (BET) of 396 m²/g (H₃PO₄-activated biochar) and 199 m²/g (KOH-activated biochar). For both activated biochars, the kinetics of adsorption of acetaminophen and amoxicillin were better described using the general order model. The isotherms of adsorption were better described by the Freundlich model (H₃PO₄-activated biochar) and the Langmuir model (KOH-activated biochar).

Characterization of graphene oxide-ziziphus seeds and its application as a hazardous dye removal adsorbent

The zizphus seeds are considered as a biomaterial residues that has been used for removing of organic industrial waste such as 2-((10-octyl-9,10-dihydroanthracene-2-yl) methylene) malononitrile (PTZS-CN) dye from aqueous solutions utilizing graphene oxide-Ziziphus (GO-Ziziphus). A batch study explored the impacts of various experimental circumstances, including solution pH, initial dye concentration, temperature, and contact time. General order, nonlinear pseudo-first order and pseudo-second order, elvoich model and intraparticiple diffusion were utilized to analyze the kinetic data. The adsorption kinetics of dye onto GO-ziziphus adsorption was best mentioned by nonlinear pseudo-first order. Similarly, the intra-particle diffusion plots revealed one exponential line throughout the adsorption process. The Freundlich, Dubinin-Radushkevich, and Langmuir models were employed to examine isothermal data. It provided the best fit of the dye adsorption isothermal data onto GO-ziziphus Freundlich models. Besides, the calculated free energies showed that the adsorption progression was physical adsorption. Thermodynamic calculations revealed that dye adsorption onto GO-ziziphus was exothermic and spontaneous. The combined results indicated that GO-ziziphus powder might be used to treat dye-rich wastewater effectively.

Facile Synthesis of Sustainable Activated Biochars with Different Pore Structures as Efficient Additive-Carbon-Free Anodes for Lithium- and Sodium-Ion Batteries

The present work elucidates facile one-pot synthesis from biomass forestry waste (Norway spruce bark) and its chemical activation yielding high specific surface area (S _BET) biochars as efficient lithium- and sodium-ion storage anodes. The chemically activated biochar using ZnCl₂ (Biochar-1) produced a highly mesoporous carbon containing 96.1% mesopores in its structure as compared to only 56.1% mesoporosity from KOH-activated biochars (Biochar-2). The latter exhibited a lower degree of graphitization with disordered and defective carbon structures, while the former presented more formation of ordered graphite sheets in its structure as analyzed from Raman spectra. In addition, both biochars presented a high degree of functionalities on their surfaces but Biochar-1 presented a pyridinic-nitrogen group, which helps improve its electrochemical response. When tested electrochemically, Biochar-1 showed an excellent rate capability and the longest capacity retentions of 370 mA h g^-1 at 100 mA g^-1 (100 cycles), 332.4 mA h g^-1 at 500 mA g^-1 (1000 cycles), and 319 mA h g^-1 at 1000 mA g^-1 after 5000 cycles, rendering as an alternative biomass anode for lithium-ion batteries (LIBs). Moreover, as a negative electrode in sodium-ion batteries, Biochar-1 delivered discharge capacities of 147.7 mA h g^-1 at 50 mA g^-1 (140 cycles) and 126 mA h g^-1 at 100 mA g^-1 after 440 cycles.

Use of Biochar Prepared from the Açaí Seed as Adsorbent for the Uptake of Catechol from Synthetic Effluents

This work proposes a facile methodology for producing porous biochar material (ABC) from açaí kernel residue, produced by chemical impregnation with ZnCl2 (1:1) and pyrolysis at 650.0 °C. The characterization was achieved using several techniques, and the biochar material was employed as an adsorbent to remove catechol. The results show that ABC carbon has hydrophilic properties. The specific surface area and total pore volume are 1315 m2·g−1 and 0.7038 cm3·g−1, respectively. FTIR revealed the presence of oxygenated groups, which can influence catechol adsorption. The TGA/DTG indicated that the sample is thermally stable even at 580 °C. Adsorption studies showed that equilibrium was achieved in <50 min and the Avrami kinetic model best fits the experimental data, while Freundlich was observed to be the best-fitted isotherm model. Catechol adsorption on ABC biochar is governed by van der Waals forces and microporous and mesoporous filling mechanisms. The Qmax is 339.5 mg·g−1 (40 °C) with 98.36% removal of simulated effluent, showing that açaí kernel is excellent biomass to prepare good biochar that can be efficiently used to treat real industrial effluents.

Composite of methyl polysiloxane and avocado biochar as adsorbent for removal of ciprofloxacin from waters

Two carbon composite materials were prepared by mixing avocado biochar and methyl polysiloxane (MK). Firstly, MK was dissolved in ethanol, and then the biochar was added at different times. In sample 1 (R1), the time of adding biochar was immediately after dissolving MK in ethanol, and in sample 2 (R₂), after 48 h of MK dissolved in ethanol. The samples were characterized by nitrogen adsorption/desorption measurements obtaining specific surface areas (S_BET) of 115 m2 g^-1 (R₁) and 580 m2 g^-1 (R₂). The adsorbents were further characterized using scanning electron microscopy, FTIR and Raman spectroscopy, adsorption of vapors of n-heptane and water, thermal analysis, Bohem titration, pHpzc, and C H N elemental analysis. R₁ and R₂ adsorbents were employed as adsorbents to remove the antibiotic ciprofloxacin from the waters. The t_1/2 and t_0.95 based on the interpolation of Avrami fractional-order were 20.52 and 246.4 min (R₁) and 14.00 and 157.6 min (R₂), respectively. Maximum adsorption capacities (Q_max) based on the Liu isotherm were 10.77 (R₁) and 63.80 mg g^-1 (R₂) for ciprofloxacin. The thermodynamic studies showed a spontaneous and exothermic process for both samples, and the value of ΔH° is compatible with physical adsorption.

Brewer’s Spent Grain Biochar: Grinding Method Matters

The present work is based on the principle of biomass waste valorization. Brewer’s spent grains (BSG) come from breweries as by-products. Their huge amount of production on an industrial scale should focus our attention on their valorization, which creates challenges as well as opportunities. One way to valorize BSG by-products is to convert them into biochar, a functional material with multiple potential applications. With an emphasis on sustainable development and the circular economy, in this work, we focused on a comparative study of the different mechanical processes of BSG grinding and their effect on the resulting biochar formed after pyrolysis. Home appliances such as blenders, coffee mills, and mortar and pestles were used for this purpose. FESEM images confirmed the successful creation of five different morphologies from the same BSG under the same pyrolysis conditions. Interestingly, a novel Chinese tea leaf egg-like biochar was also formed. It was found that a series of physical pretreatments of the biomass resulted in the reduced roughness of the biochar surface, i.e., they became smoother, thus negatively affecting the quality of the biochar. XRD revealed that the biomass physical treatments were also reflected in the crystallinity of some biochar. Via a Raman study, we witnessed the effect of mechanical pressure on the biomass for affecting the biochar features through pressure-induced modifications of the biomass’s internal structure. This induced enhanced biochar graphitization. This is a good example of the role of mechanochemistry. DSC revealed the thermochemical transformation of the five samples to be exothermic reactions. This study opens up an interesting possibility for the synthesis of biochar with controlled morphology, crystallinity, degree of graphitization, and heat capacity.

Preparation and Characterization of Pulp and Paper Mill Sludge-Activated Biochars Using Alkaline Activation: A Box-Behnken Design Approach

This study utilized pulp and paper mill sludge as a carbon source to produce activated biochar adsorbents. The response surface methodology (RSM) application for predicting and optimizing the activated biochar preparation conditions was investigated. Biochars were prepared based on a Box-Behnken design (BBD) approach with three independent factors (i.e., pyrolysis temperature, holding time, and KOH:biomass ratio), and the responses evaluated were specific surface area (SSA), micropore area (S _micro), and mesopore area (S _meso). According to the RSM and BBD analysis, a pyrolysis temperature of 800 °C for 3 h of holding and an impregnation ratio of 1:1 (biomass:KOH) are the optimum conditions for obtaining the highest SSA (885 m² g^-1). Maximized S _micro was reached at 800 °C, 1 h and the ratio of 1:1, and for maximizing S _meso (569.16 m² g^-1), 800 °C, 2 h and ratio 1:1.5 (445-473 m² g^-1) were employed. The biochars presented different micro- and mesoporosity characteristics depending on pyrolysis conditions. Elemental analysis showed that biochars exhibited high carbon and oxygen content. Raman analysis indicated that all biochars had disordered carbon structures with structural defects, which can boost their properties, e.g., by improving their adsorption performances. The hydrophobicity-hydrophilicity experiments showed very hydrophobic biochar surfaces. The biochars were used as adsorbents for diclofenac and amoxicillin. They presented very high adsorption performances, which could be explained by the pore filling, hydrophobic surface, and π-π electron-donor-acceptor interactions between aromatic rings of both adsorbent and adsorbate. The biochar with the highest surface area (and highest uptake performance) was subjected to regeneration tests, showing that it can be reused multiple times.