Adsorption Of Phenol Research Articles

Cross-polymerization between bio-oil and polyaniline: synergistic effects on pore development in subsequent activation and adsorption of phenol

The preparation of nitrogen-containing porous carbon by cross-polymerization of polyaniline and bio-oil during activation process for phenol adsorption.

Surface accumulation and acid-base equilibrium of phenol at the liquid-vapor interface.

We have investigated the surfactant properties of phenol in aqueous solution as a function of pH and bulk concentration using liquid-jet photoelectron spectroscopy (LJ-PES) and surface tension measurements. The emphasis of this work is on the determination of the Gibbs free energy of adsorption and surface excess of phenol and its conjugate base phenolate at the bulk pKa (9.99), which can be determined for each species using photoelectron spectroscopy. These values are compared to those obtained in measurements well below and well above the pKa, where pure phenol or phenolate, respectively, are the dominant species, and where the Gibbs free energy of adsorption determined from surface tension and LJ-PES data are in excellent agreement. At the bulk pKa the surface-sensitive LJ-PES measurements show a deviation of the expected phenol/phenolate ratio in favor of phenol, i.e., an apparent upward shift of the at the surface. In addition, the Gibbs free energies of adsorption determined by LJ-PES at the bulk pKa for phenol and phenolate deviate from those observed for the pure solutions. We discuss these observations in view of the different surface propensity of phenol and phenolate as well as potential cooperative interactions between them in the near-surface region.

Modeling of multicomponent adsorption equilibria of phenol and ciprofloxacin on pristine, acid-modified and thermo-oxidatively-aged polyethylene terephthalate microplastics

Abstract Multicomponent systems are representative of the most common real situations as many industrial discharges contain a mixture of several pollutants. This study examines the concurrent adsorption of phenol (PHE) and ciprofloxacin (CIP) onto three types of polyethylene terephthalate microplastics (PET MPs): pristine, acid-modified, and thermal-oxidatively aged. Using extended Langmuir (EL), extended Freundlich (EF) isotherms, and a new artificial neural network (ANN) model, equilibrium adsorption capacities were predicted. The EL isotherm fit for pristine and aged PET MPs, while EF fit for modified PET MPs. Monolayer adsorption capacities ranged from 342.10–3715.73 mg/g for PHE and 2518.23–14498.79 mg/g for CIP, exceeding single-component adsorption. The ANN model used one hidden layer with 3 neurons for pristine and aged PET MPs, and 2 hidden layers with five neurons for modified PET MPs, with a hyperbolic tangent activation function. Models showed excellent performance metrics, including R2 values of 0.989–0.999, RMSE of 0.001–0.413, and AAE of 0.009–0.327. Synergistic interactions were observed in the binary system, with PET MPs showing higher selectivity toward CIP. The study demonstrates the effectiveness of PET MPs for binary adsorption of PHE and CIP in aqueous solutions, highlighting their potential for multicomponent pollutant removal.

Use of murici (Byrsonima crassifolia) and jabuticaba (Plinia cauliflora) residues in the preparation of porous materials: Effect of pH on the adsorption efficiency of the contaminants phenol, diethylphthalate and amoxicillin

Activated charcoals with the chemical activator (H3PO4) were synthesized from agro-industrial residues, Murici seeds (CA-MU) and Jabuticaba (CA-JA). The synthesized charcoals were characterized by thermogravimetric analysis (TG), N2 adsorption and desorption isotherms, Fourier transform infrared spectroscopy (FTIR), point of zero charge (pHPZC) and scanning electron microscopy (SEM). The charcoals produced presented mesoporous characteristics, surface areas of 884.226 m2.g−1 for CA-JA and 556.97 m2.g−1 for CA-MU, mean pore diameters suitable for adsorption of phenol (PHE), diethylphthalate (DEP) and amoxicillin (AMX). The chemical characterization indicated the acid profile of the surface of the charcoals, which presented pHPZC of 6.3 (CA-JA) and 6.7 (CA-MU). The adsorption studies, in aqueous solution of the pollutants (PHE), (DEP) and (AMX), indicated that the removal capacity is strongly influenced by the pH of the solution. Toxicity tests demonstrated that the adsorption process was responsible for decreasing the toxicity of the pollutants studied. Thus, given the results presented, the activated charcoals synthesized can be considered high potential adsorbents for applications in the removal of organic pollutants in aqueous solutions.

Development of new effective activated carbon supported alkaline adsorbent used for removal phenolic compounds

Phenolic (phenol) compounds are the major contaminates in wastewater, which can have a considerable negative influence on the environment and health of human. Adsorption is an efficient process that is widely applied in order to eliminate phenol in wastewater. In recent, Adsorption process has acquired a lot of attentiveness owing to its relative moderate operating conditions. However, adsorption process needs considerable ameliorations in terms of adsorbent modification, process type, productivity, and conversion rate. This work studies the development of a fast and effective adsorption process in a fixed bed adsorption column (FBAC) in order to reach safe and continuous elimination of phenolic compounds. Several adsorption parameters (reaction temperature, adsorbent bed height, feed flow rate and kind of adsorbent) were studied to achieve the highest removal of phenolic compounds. The adsorption process was conducted in the presence of two type of adsorbents (activated carbon (AC), and KOH/AC), 73% and 94% of phenol elimination were attained, respectively, at 10 cm bed height, 1 ml/s feed flow rate, and 75 °C reaction temperature. The adsorbents activity was investigated after six consecutive adsorption cycles at the best process conditions, and the adsorbents show high stability in terms of phenolic compounds adsorption. After that, the spent adsorbents were regenerated by utilizing various solvents (methanol, ethanol and iso-octane), and the results show that iso- octane achieved highest regeneration efficiency. The adsorption process was implemented in the adsorption column that the performance is possibly to be adjusted at an industrial scale since it can be scaled up predictably.

Reactant enrichment in yolk-shell structured Pd/TiN nanoreactors for boosting electrocatalytic hydrodechlorination performance

Enhancing the enrichment behavior of low-concentration chlorinated organic pollutants remains a significant challenge in electrocatalytic hydrodechlorination (EHDC) technology. Metal-loaded hollow nanoarchitecture has emerged as a promising nanoreactor to improve reaction enrichment behavior because of its tailorable microenvironments and electronic properties. Herein, a structural engineering strategy is developed to synthesize yolk-shell structured TiN spheres supported Pd nanoreactors (Pd/YS-TiN) with confined mesoscopic spaces. Characterization by multiple techniques reveals that the yolk-shell structure of YS-TiN, with high specific surface area (139.0 m2/g) and appropriately mesoporosity (6.9 nm), exposes numerous Pd nanoparticles (∼4.0 nm) on outer/inner surface of the shell and yolk-core solid sphere, ensuring an efficient utilization of active sites for enhancing the 2,4-DCP detoxification. Consequently, the structurally optimized Pd/YS-TiN nanoreactor consistently displays maximum reaction kinetics, dechlorination degree, faradaic current density, H* utilization and product selectivity, surpassing hollow TiN-supported Pd and Pd/C catalysts. The super EHDC performance of 91.8 % 2,4-DCP conversion, a specific activity of 1.68 min−1 molPd−1, and a mass activity of 6.06 min−1 gPd−1 is obtained at −0.85 V and 180 min, outperforming most reported catalysts. Combining experimental and density functional theory results, the exceptional reaction enrichment behavior of Pd/YS-TiN originates from (1) alleviating the overstrong adsorption of product phenol through strong metal-support interactions and (2) enhancing mass transport efficiency facilitated by the local concentration gradient and mesoporous shell. This study elucidates how metal-support interactions and mass transport synergistically enhance reaction enrichment behavior, showcasing potential benefits in environmental remediation applications.

Molecular simulation of adsorption behavior for phenol aqueous solution into layered graphene oxides

Graphene oxide (GO) adsorbents possess layered structures with nanoscale interlayer channels, which have been proposed as effective adsorbents for the removal of harmful phenol from aqueous solutions. However, the relevant adsorption process and behavior remain largely unexplored, and, particularly, the interlayer insertion and interaction mechanism need to be clarified. Herein, molecular dynamics simulation was performed to comprehensively investigate the dynamics process and interaction for phenol adsorption into GO interlayers. It is theoretically demonstrated that the adsorption process is thermodynamically spontaneous. The time evolution of molecular insertion amounts and interaction energy were applied to describe the dynamics process, in which different adsorption stages were revealed. Our simulation findings show that the interlayer phenol movement is the rate-limiting step in the adsorption process. Furthermore, by analyzing the interlayer structure and morphology, it is illustrated that the phenol molecules are discretely and disorderly scattered with a lying-down conformation within the GO interlayer. The adsorption interaction is the combination of the π–π and hydrogen-bonding interactions, in which the π-π interaction provides a dominant contribution. The effects of interlayer widths and surface oxidization degrees were thoroughly investigated. Our simulations provide new insight and useful guidance for the development of GO adsorbents.

Adsorption and Kinetic study of priority organic pollutant phenol from aqueous waste using Activated carbon

Many organic compounds present in industrial and domestic wastewater are carcinogenic in nature. Removal of these organic compounds from waste waters has become a great challenge to waste water treatment technologies as many of them are non-biodegradable in nature. Adsorption on activated carbon has emerged as an efficient and economically viable technology for the removal of a broad spectrum of toxic organic compounds from domestic and industrial waste water. The adsorption of hazardous organic compounds on activated carbon has been the subject of research for the past three decades. In the present study, kinetic study for adsorption of some priority organic pollutants like phenol on activated carbon, was studied at laboratory scale. Series of experiments were carried out to determine kinetics for adsorbate, when present in aqueous solution as a single component. The commercially available bituminous coal based activated carbon Filtrasorb-400 was used as an adsorbent. A simplified interpretation of the kinetic data based on Langmuir theory has been used. The kinetics performed gives the adsorption equilibrium time. The adsorption and desorption rate constants were evaluated from the graph.

Enhanced adsorption of phenol using graphene oxide-bentonite nanocomposites: Synthesis, characterisation, and optimisation

Wastewater treatment is crucial because it causes harm to the environment of human beings. Adsorbents are faulted by low adsorption capacity and difficult recovery due to organic pollutants. This study aims to improve adsorption capacities using bentonite and other environmentally friendly and economically feasible adsorbents. To do this, using Hammer's approach, bentonite was subjected to an acidic treatment (1.5 M H2SO4) and then hybridized with synthetic graphene oxide (GO). Integrating GO nanosheets within the interlayer of acid-activated bentonite and depositing them onto the exterior surface using a simple ultrasonic-assisted method successfully created a graphene oxide-bentonite nanocomposite. GO, and its composites (at 5 and 10 wt%) were characterized using ATR-FTIR, BET, XRD, FE-SEM, and AFM studies. The results demonstrated that GO with a single-layer thickness of 0.618 nm could be successfully fabricated. We employed energy-dispersive X-ray spectroscopy (EDX) to detect changes in chemical composition before and after phenol adsorption. It was thoroughly studied how essential factors, including adsorbent dosage, pH, agitation period, and beginning phenol concentration, affected adsorption behavior. An obvious increases of the adsorption capacities from 30.69 to 46.43 mg/g were achieved under ideal circumstances of pH 6, an 8-hour contact duration, and doses of 0.3 g and 0.2 g for GO-MB5 and GO-MB10 composites, respectively. The pseudo-second-order kinetic and Langmuir equilibrium isotherm models efficiently described the adsorption process. More notably, the synthesized adsorbents could be successfully regenerated and used without major capacity losses after six cycles. This study highlights the effectiveness of GO-bentonite nanocomposites as effective adsorbents for environmental treatment.

Sustainable waste utilization: Geopolymeric fly ash waste as an effective phenol adsorbent for environmental remediation

Rapid industrialization and urbanization generate significant waste, including fly ash, posing environmental challenges. Utilizing these materials is essential to mitigate impacts and promote sustainable development. This research paper focuses on the innovative application of geopolymeric fly ash (GEOFA) waste modified with titanium oxide (TiO2) (GEOFA-TiO2) as a promising adsorbent for the removal of phenol compounds from contaminated water. Analysis showed that the modification process resulted in the formation of functional groups such as -OH, which aided in the adsorption process. Adsorption studies were conducted to evaluate the influence of pH, temperature, and concentration on phenol removal. The maximum percentage removal of phenol was achieved at optimum conditions of pH 6 and a temperature of 25 °C, with an adsorption capacity of 166.7 mg/g. The adsorption process followed the Langmuir model, suggesting a monolayer adsorption mechanism and the thermodynamic studies revealed that the phenol adsorption onto GEOFA-TiO2 was an endothermic process with a promising affinity between phenol and the adsorbent. This study demonstrates the effective use of modified fly ash-based adsorbents to remove phenolic contaminants. By repurposing waste materials, this research addresses waste management challenges and promotes sustainable practices, reveling their potential for environmental remediation.

Evaluation of Functional Spray Coatings for Mitigating the Uptake of Volatile Phenols by Pinot Noir Wine Grapes via Blocking, Absorption, and/or Adsorption.

Spray coatings have shown promising potential in preventing the uptake of smoke phenols from wildfires into wine grapes. Three cellulose nanofiber-based coatings with low methoxyl pectin or varying concentrations of chitosan were made into films and their potential for blocking, absorption, or adsorption of phenols (guaiacol, m-cresol, and syringol) was evaluated using a custom-built smoke diffusion box. The coatings were also applied to Pinot noir grapes in a vineyard. GC-MS analysis for smoke phenols from headspace gases of diffusion study and extractions of films indicated that chitosan-based films can block guaiacol and syringol, and all films are able to capture m-cresol. The type of coating and application time in a vineyard did not affect (P < 0.05) physicochemical properties, size, and weight of the berries, whereas chitosan-based coatings resulted in a higher anthocyanin content of berries. This study provided new information about the key mechanisms (i.e., blocking phenols) of coatings to mitigate smoke phenol uptake in wine grapes.

Phenol Adsorption Performance of Nitrogen-Doped Porous Carbon Derived from Silicon Oxycarbide Ceramics

Phenol Adsorption Performance of Nitrogen-Doped Porous Carbon Derived from Silicon Oxycarbide Ceramics

Surface functionalization of magnetite nanoparticles for remediation enhancement of phenol from aqueous solutions

Phenol is a toxic pollutant generated by industries. It can diminish the supply of clean water and is hazardous to human health. Hence, an effective abatement method is important to remove phenol from water sources. The following amine-functionalized magnetite nanoparticles, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and polyethylenehexamine (PEHA), were used to study the adsorption performances of phenol from the prepared samples. The morphological study revealed long rod shapes with rough and sharp edges, while the elemental analysis presented the addition of two elements, C and N atoms. In addition, the TETA@MNP possessed weaker magnetism compared to MNPs, showing that the surface functionalization of MNPs was successful. TETA@MNP showed the highest percentage for phenol removal compared to others. The TETA@MNP achieved a removal efficiency of 99.2% at optimum conditions of 60 mg dosage, contact time of 25 min, and pH of 7. TETA@MNP obeyed the pseudo-second-order kinetic model and the Freundlich isotherm model, with coefficients of determination (R2) of 0.9765 and 0.9682, respectively. The reusability study has demonstrated that TETA@MNP can be reused approximately 6 times with extremely minor loss. Therefore, TETA@MNP is a good adsorbent for the adsorption of phenol from prepared sample solutions.

Hybrid electromagnetic field-flow by electrode configuration for the removal of phenol from contaminated water

In this study, we introduce an electrode configuration setup to study the effect of an electromagnetic field (EMF) and electric potential (EP) on phenol removal in a continuous adsorption process. Feed water contaminated with dissolved phenol was exposed to EMF and passed through charged activated carbon electrodes prepared from Phoenix dactylifera (palm tree) biowaste. This study investigated the effects of magnetic field exposure, electric potential, feed salinity, and electrode substrate type. The results revealed that the highest adsorption uptake capacity of 47.2 mg/g was achieved using an aluminum substrate (AS) with EMF at zero salinity. The phenol adsorption kinetics followed a pseudo-second-order adsorption rate and diffusion model, indicating that intraparticle diffusion was the primary rate-limiting mechanism. The increased phenol adsorption uptake capacity brought on by the EMF may result from the improved mass transfer and mobility of the adsorbate and, consequently, the increased effectiveness of the internal diffusion of the pollutants. Finally, a regeneration efficiency of 99 % was achieved using NaOH at a salinity of 5,000 ppm.

Adsorption of pyrolysis oil model compound (phenol) with plasma-modified hydro-chars and mechanism exploration.

Phenol is one of the important ingredients of pyrolysis oil, contributing to the high biotoxicity of pyrolysis oil. To promote the degradation and conversion of phenol during anaerobic digestion, cheap hydro-chars with high phenol adsorption capacity were produced. The phenol adsorption capabilities of the plain hydro-char, plasma modified hydro-char at 25°C (HC-NH3-P-25) and 500°C (HC-NH3-P-500) were evaluated, and their adsorption kinetics and thermodynamics were explored. Experimental results indicate that the phenol adsorption capability of HC-NH3-P-500 was the highest. The phenol adsorption kinetics of all samples followed the pseudo-second-order equation and interparticle diffusion model, indicating that the adsorption rate of phenol was controlled by interparticle diffusion and chemistry adsorption simultaneously. By DFT calculations, π-π stacking and hydrogen bond are the main interactions for phenol adsorption. It was observed that an enriched graphite N content decreased the average vertical distance between hydro-chars and phenol in π-π stacking complex, from 3.5120 to 3.4532Å, causing an increase in the negative adsorption energy between phenol and hydro-char from 13.9330 to 23.4181kJ/mol. For hydrogen bond complex, the average vertical distance decreased from 3.4885 to 3.3386Å due to the increase in graphite N content; causing the corresponding negative adsorption energy increased from 19.0233 to 19.9517kJ/mol. Additionally, the presence of graphite N in the hydro-char created a positive diffusion region and enhanced the electron density between hydro-char and phenol. Analyses suggest that enriched graphite N contributed to the adsorption complex stability, resulting in an improved phenol adsorption capacity.

A novel ZIF-8@IL-MXene/poly (N-isopropylacrylamide) nanocomposite hydrogel toward multifunctional adsorption

Phenols, dyes, and metal ions present in industrial wastewater can adversely affect the environment and leach biological carcinogens. Given that the current research focuses only on the removal of one or two of those categories. Herein, this work reports a novel ZIF-8@IL-MXene/Poly(N-isopropylacrylamide) (NIPAM) nanocomposite hydrogel that can efficiently and conveniently absorb and separate multiple pollutants from industrial wastewater. Ionic liquid (IL) was grafted onto MXene surfaces using a one-step method, and then incorporated into NIPAM monomer solutions to obtain the IL-MXene/PNIPAM composite hydrogel via in-situ polymerization. ZIF-8@IL-MXene/PNIPAM nanocomposite hydrogels were obtained by in-situ growth of ZIF-8 on the pore walls of composite hydrogels. As-prepared nanocomposite hydrogel showed excellent mechanical properties and can withstand ten repeated compressions without any damage, the specific surface area increased by 100 times, and the maximum adsorption capacities for p-nitrophenol (4-NP), crystal violet (CV), and copper ion (Cu2+) were 198.40, 325.03, and 285.65 mg g−1, respectively, at room temperature. The VPTTs of all hydrogels ranged from 33 to 35 °C, so the desorption process can be achieved in deionized water at 35–40 °C, and its adsorption capacities after five adsorption-desorption cycles decreased to 79%, 91%, and 29% for 4-NP, CV, and Cu2+, respectively. The adsorption data fitting results follow pseudo-second-order kinetics and Freundlich models, which is based on multiple interactions between the functional groups contained in hydrogels and adsorbent molecules. The hydrogel is the first to realize the high-efficiency adsorption of phenols, dyes and metal ions in industrial wastewater simultaneously, and the preparation process of hydrogels is environmentally friendly. Also, giving hydrogel multifunctional adsorption is beneficial to promote the development of multifunctional adsorption materials.

Synergistic Roles of the CoO/Co Heterostructure and Pt Single Atoms for High-Efficiency Electrocatalytic Hydrogenation of Lignin-Derived Bio-Oils.

Electrochemical hydrogeneration (ECH) of biomass-derived platform molecules, which avoids the disadvantages in utilizing fossil fuel and gaseous hydrogen, is a promising route toward value-added chemicals production. Herein, we reported a CoO/Co heterostructure-supported Pt single atoms electrocatalyst (Pt1-CoO/Co) that exhibited an outstanding performance with a high conversion (>99%), a high Faradaic efficiency (87.6%), and robust stability (24 recyclability) at -20 mA/cm2 for electrochemical phenol hydrogenation to high-valued KA oil (a mixture of cyclohexanol and cyclohexanone). Experimental results and the density functional theory calculations demonstrated that Pt1-CoO/Co presented strong adsorption of phenol and hydrogen on the catalyst surface simultaneously, which was conducive to the transfer of the adsorbed hydrogen generated on the single atom Pt sites to activated phenol, and then, ECH of phenol with high performance was achieved instead of the direct hydrogen evolution reaction. This work described that the multicomponent synergistic single atom catalysts could effectively accelerate the ECH of phenol, which could help the achievement of large-scale biomass upgrading.

Study on the biodegradation of phenol by Alcaligenes faecalis JH1 immobilized in rice husk biochar

Immobilized microbial technology is a sustainable solution to reduce water pollution. Understanding the microorganisms in immobilized biochar is critical for the removal of contaminants in water. Biochar as a carrier of microorganisms, there are some problems need to be focused on, microporous structure blockage limiting the contact between microorganisms and pollutants for further degradation, unstable microbial loading, and low cycle times. To solve these problems, Alcaligenes faecalis was immobilized with rice hull biochar to study its adsorption and degradation characteristics of phenol. It was found that A. faecalis JH1 could effectively remove 300 mg/L of phenol within 24 h. The adsorption capacity of rice husk biochar for phenol increased with the increasing pyrolysis temperature (700 &amp;gt; 500&amp;gt;300°C). The immobilized biomass of JH1 from 700°C rice husk biochar reached 249.45 nmol P/g at 24 h of fixation reaction. It was found that the phenol removal rate of JH1 immobilized at all temperature biochar reached 300 mg/L within 12 h after the sixth cycle. As the number of cycles increased, bacteria grew and adhered to the biochar, forming a thick viscous biofilm and accelerating the removal of phenol. The results showed that A. faecalis could firmly adhere to rice hull biochar and degrade phenol effectively, with good durability and cyclicity.

Linear and nonlinear regression analysis of phenol and P-nitrophenol adsorption on a hybrid nanocarbon of ACTF: kinetics, isotherm, and thermodynamic modeling

This study aimed to create activated carbon thin film (ACTF) as a hybrid nanocarbon via a simple and efficient method through a single-step mixing process using thermal functionalization techniques. TEM, BET, BJH, FTIR, XRD, and TGA analyses were used to investigate the prepared ACTF. The results exhibited that ACTF has a porous structure with a high surface area of 318 m2/g and important functional groups, which are considered significant adsorption sites. The adsorption performance of ACTF for phenol and p-nitrophenol (PNP) removal from aqueous solutions using batch adsorption mode was studied. Evaluations were conducted on experimental factors influencing the adsorption process, such as pH, initial phenol and PNP concentrations, adsorbent dose, contact time, and temperature. Under the optimized conditions, the phenol and PNP were removed with a maximum efficiency of 89.98% and 92.5%, respectively. The results of linear and nonlinear isotherms and kinetic models of phenol and PNP showed that both pollutants were well fitted with the Freundlich model (R2 = 0.99, χ2 = 0.13, RMSE = 1.6), (R2 = 0.99, χ2 = 0.42, RMSE = 2.8), and the pseudo-second-order model (R2 = 0.999, χ2 = 0.03, RMSE = 0.31), (R2 = 0.99, χ2 = 0.01, RMSE = 0.24), for phenol and PNP, respectively. According to the calculated thermodynamic results, the adsorption of phenol and p-nitrophenol onto the ACTF surface was a spontaneous and exothermic reaction. The regeneration experiments showed that the spent ACTF could be reused up to the fifth cycle while maintaining noteworthy removal efficiency.

Activation of lignin-derived biochar with mixed H2O and CO2: Characterization of reaction intermediates and investigation their potential synergistic effects

Physical activation of biomass with H2O or CO2 is an important method for producing activated carbon (AC). Activation of biomass with CO2 or H2O follows varied mechanisms and the use of mixed CO2/H2O might show potential synergistic effects for creating pores. This was investigated by activation of lignin-derived biochar with H2O, CO2 and their mixture. The results demonstrated that H2O as an activator was much more effective than CO2 for generation of pores (804.1 m2g−1 versus 516.1 m2g−1in CO2), especially mesopores (40% versus 14% in CO2). This was achieved via enhancing cracking/gasification reactions of the biochar with H2O. The synergistic effect of CO2 and H2O for activation of the lignin-derived biochar was insignificant as cracking/gasification reactions were not enhanced, leading to remarkably lower specific surface area of the AC (674.8 m2g−1) than that with H2O as an activator alone. Competitive adsorption of CO2 and H2O existed and preferable adsorption of CO2 hindered deoxygenation of the biochar with H2O. The in-situ IR characterization indicated that CO2 presence suppressed decarbonylation reactions, retaining more oxygen species in form of CO, while it was the opposite in H2O. Additionally, activation with H2O formed numerous round-shape dents on surface of activated carbon, while the activation with CO2 formed the characteristic round edges. The AC activated with H2O showed superior capability for adsorption of phenol than that activated with CO2 or mixed H2O/CO2.