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For the preparation of activated carbon papers (APCs) as supercapacitor electrodes, impurity substances were removed from rice husks, before carbonization and various activation temperature treatments, to optimize electro chemical efficiency. The porosities and electrochemical performances of the ACPs depended strongly on activation temperature: The specific surface area increased from 202.92 (500 &deg, C) to 2158.48 m2 g&minus, 1 (1100 &deg, C). XRD and Raman analyses revealed that ACP graphitization also increased with the activation temperature. For activation at 1100 &deg, C, the maximum specific capacitance was 255 F g&minus, 1, and over 92% of its capacitance was retained after 2000 cycles.

The wide occurrence of pharmaceuticals in aquatic environments urges the development of cost-effective solutions for their removal from water. In a circular economy context, primary paper mill sludge (PS) was used to produce activated carbon (AC) aiming the adsorptive removal of these contaminants. The use of low-cost precursors for the preparation of ACs capable of competing with commercial ACs continues to be a challenge. A full factorial design of four factors (pyrolysis temperature, residence time, precursor/activating agent ratio, and type of activating agent) at two levels was applied to the production of AC using PS as precursor. The responses analysed were the yield of production, percentage of adsorption for three pharmaceuticals (sulfamethoxazole, carbamazepine, and paroxetine), specific surface area (S ), and total organic carbon (TOC). Statistical analysis was performed to evaluate influencing factors in the responses and to determine the most favourable production conditions. Four ACs presented very good responses, namely on the adsorption of the pharmaceuticals under study (average adsorption percentage around 78%, which is above that of commercial AC), and S between 1389 and 1627 m g . A desirability analysis pointed out 800 °C for 60 min and a precursor/KOH ratio of 1:1 (w/w) as the optimal production conditions., This work was funded by FEDER through COMPETE 2020 and by national funds through FCT by the research project PTDC/AAG-TEC/ 1762/2014. Thanks are also due for the financial support to CESAM (UID/AMB/50017-POCI-01-0145-FEDER-007638), to FCT/MCTES through national funds (PIDDAC), and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. The work was also developed within the scope of the project CICECO - Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (UID/ CTM/50011/2013), financed by national funds through the FCT/MEC. Vânia Calisto also thanks FCT for her postdoctoral grant (SFRH/BPD/ 78645/2011). Marta Otero and Sérgio Santos thank support by the FCT Investigator Program (IF/00314/2015 and IF/00973/2014, respectively).

The current investigation deals with how chemically activated carbon derived from industrial paper sludge (ACPS) performs on sorptive removal of enrofloxacin (ENF), an antibacterial drug from its water solution. Thermogravimetric (TGA) and proximate analysis of raw paper sludge (RPS) were conducted. ACPS was characterized with proximate analysis, XRD, FT-IR, SEM and BET. The influence of five operational parameters viz. adsorbate concentration (initial), dose of adsorbent, pH, temperature, and contact time on the adsorption of ENF onto ACPS has been conducted using batch experiments. The process of adsorption was optimized through ANN (artificial neural network) in addition to RSM (response surface methodology). The maximum percentage removal (95.85%) was achieved at initial ENF concentration 12 mg/g, adsorbent dose 1.2 g/L, contact duration of 18 h and temperature 20 °C. Kinetic data were best fitted into pseudo-second order kinetic model and adsorption equilibrium study indicates that the adsorption process follows Langmuir isotherm model. Adsorption capacity was noted to have a highest value of 44.44 mg/g. A study on thermodynamics of the adsorption process suggests that it exhibits spontaneity, being essentially exothermic. Cost analysis and reusability study confirm that adsorbent produced from industrial paper sludge is cost-effective and reusable. Therefore, ACPS as adsorbent has potency for removing ENF from aqueous solution.

Biochar microparticles were prepared from three different types of biochar, derived from waste materials, such as pine wood (BC-PW), pig manure (BC-PM) and cardboard (BC-PD) under various pyrolysis conditions. The microparticles were prepared by dry grinding and sequential sieving through various ASTM sieves. Particle size and specific surface area were analyzed using laser particle size analyzer. The particles were further characterized using scanning electron microscope (SEM). The adsorption capacity of each class of adsorbent was determined by methylene blue adsorption tests in comparison with commercially available activated carbon. Experimental results showed that dye adsorption increased with initial concentration of the adsorbate and biochar dosage. Biochar microparticles prepared from different sources exhibited improvement in adsorption capacity (7.8±0.5 mg g(-1) to 25±1.3 mg g(-1)) in comparison with raw biochar and commercially available activated carbon. The adsorption capacity varied with source material and method of production of biochar. The maximum adsorption capacity was 25 mg g(-1) for BC-PM microparticles at 25°C for an adsorbate concentration of 500 mg L(-1) in comparison with 48.30±3.6 mg g(-1) for activated carbon. The equilibrium adsorption data were best described by Langmuir model for BC-PM and BC-PD and Freundlich model for BC-PW.

Catcherboard MB12® from Smurfit Kappa is a recycled paperboard incorporating activated carbon to reduce the release of contaminants into food. An approach is proposed to determine the efficacy of the activated carbon. Sorption into activated carbon increases the concentration ratio paperboard/food (distribution coefficient) and reduces the migration rate, i.e. prolongs the time for equilibration. Using silicone paper as food simulant, the concentration ratio was increased by a factor of at least 1000 compared to recycled paperboard without activated carbon, which is sufficient to meet the 1% criterion proposed for barriers. Sorbents have limited capacity. A load with in total 4000 mg surrogate substances/kg paperboard (in addition to the material from the paperboard) exceeded the capacity: concentration ratios were reduced and the release of paperboard constituents increased. Capacity is consumed by constituents from the printing inks and the packed food. Total amounts of substances in dry foods of sufficient volatility to potentially migrate into the paperboard through the gas phase at ambient temperature were determined by GC-FID. For the large majority of the dry foods, these amounts were clearly below the capacity limit even under the exaggerated assumption of total transfer. Migration of mineral oil hydrocarbons into cat food over up to 1 year was not detectable at 1 mg/kg. It is concluded that recycled paperboard with activated carbon is promising for respecting the 1% criterion stipulated for functional barriers to avoid food contamination from recycled paperboard.

Hemicelluloses and lignin present in the spent liquor (SL) of neutral sulfite semichemical (NSSC) pulping process can potentially be converted into value-added products such as furfural, hydroxymethylfurfural, levulinic acid, phenols and adhesives. However, the direct conversion of hemicelluloses and lignin of SL into value-added products is uneconomical due to the dilute nature of the SL. To have a feasible downstream process for utilizing lignocelluloses of SL, the lignocelluloses should initially be separated from the SL. In this study, an adsorption process (via applying activated carbon) was considered for isolating the dissolved lignin and hemicelluloses from the SL of an NSSC pulping process. Under the optimal conditions of pH, SL/AC weight ratio, time and temperature of 5.7, 30, 360 min and 30 °C, the maximum lignin and hemicellulose adsorptions were 0.33 and 0.25 g/g on AC. The chemical oxygen demand (COD) and turbidity of the SL were decreased by 11% and 39%, respectively, as a result of lignocellulose adsorption on AC. Also, the incineration behavior of the SL-treated AC was studied with a thermo-gravimetric analysis (TGA).

A process for removing inhibitors from pre-hydrolysis liquor (PHL) of a kraft-based dissolving pulp production process by adsorption and flocculation, and the characteristics of this process were studied. In this process, industrially produced PHL was treated with unmodified and oxidized activated carbon as an absorbent and polydiallyldimethylammonium chloride (PDADMAC) as a flocculant. The overall removal of lignin and furfural in the developed process was 83.3% and 100%, respectively, while that of hemicelluloses was 32.7%. These results confirmed that the developed process can remove inhibitors from PHL prior to producing value-added products, e.g. ethanol and xylitol via fermentation.

Recycling paper mill effluent by conventional water treatment is difficult due to the persistence of salt and recalcitrant organics. Elimination of dissolved organic matter (DOM) from paper mill effluent was studied using three treatment options, ion exchange resin (IER), granular activated carbon (GAC) and nanofiltration (NF). The removal efficiency was analysed based on hydrophobicity, molecular weight and fluorogenic origin of the DOM fractions. For IER, GAC and NF treatments, overall removal of dissolved organic carbon was 72%, 76% and 91%, respectively. Based on the hydrophobicity, all the three treatment methods majorly removed hydrophobic acid fractions (HPhoA). Further, IER acted on all fractions, 57% of HPhoA, 44% of transphilic acid and 18% of hydrophilics, substantiating that the removal is by both ion exchange and adsorption. Based on the molecular weight, IER and GAC treatments acted majorly on the high molecular weight fractions, whereas NF eliminated all molecular weight fractions. After GAC adsorption, some amount of humic hydrolysates and low molecular weight neutrals persisted in the effluent. After IER treatment, amount of low molecular weight compounds increased due to resin leaching. Qualitative analysis of fluorescence excitation emission matrices showed that the fulvic acid-like fluorophores were more recalcitrant among the various DOM fractions, considerable amount persisted after all the three treatment methods. Three treatment methods considerably differed in terms of removing different DOM fractions; however, a broad-spectrum process like NF would be needed to achieve the maximum elimination.

We develop an ozone transport and reaction model to determine reaction probabilities and assess the importance of physical properties such as porosity, pore diameter, and material thickness on reactive uptake of ozone to five materials. The one-dimensional model accounts for molecular diffusion from bulk air to the air-material interface, reaction at the interface, and diffusive transport and reaction through material pore volumes. Material-ozone reaction probabilities that account for internal transport and internal pore area, γ(ipa), are determined by a minimization of residuals between predicted and experimentally derived ozone concentrations. Values of γ(ipa) are generally less than effective reaction probabilities (γ(eff)) determined previously, likely because of the inclusion of diffusion into substrates and reaction with internal surface area (rather than the use of the horizontally projected external material areas). Estimates of γ(ipa) average 1 × 10(-7), 2 × 10(-7), 4 × 10(-5), 2 × 10(-5), and 4 × 10(-7) for two types of cellulose paper, pervious pavement, Portland cement concrete, and an activated carbon cloth, respectively. The transport and reaction model developed here accounts for observed differences in ozone removal to varying thicknesses of the cellulose paper, and estimates a near constant γ(ipa) as material thickness increases from 0.02 to 0.16 cm.

The feasibility of activated carbon post-treatment of (biologically treated) wastewater from the paper and board industry was investigated, the goal being to remove refractory organic pollutants and produce water that can be re-used in the production process. Because closing water-circuits in the paper and board industry results in higher water temperatures, the effect of the temperature on activated carbon treatment was also investigated. Batch and column adsorption tests showed that activated carbon provides an excellent removal of cationic demand and color related compounds, the two most important representatives of organic compounds that have to be removed. Unexpectedly, higher water temperatures enhanced the performance of activated carbon. However, the treatment costs, mainly determined by transport and regeneration of the carbon, were very high. At long contact times between the wastewater and the carbon the occurrence of biodegradation was observed. Biological regeneration of the carbon may therefore provide a means to reduce the treatment costs, but a practical application requires further research.

Models of reactive uptake of ozone in indoor environments generally describe materials through aerial (horizontal) projections of surface area, a potentially limiting assumption for porous materials. We investigated the effect of changing porosity/pore size, material thickness, and chamber fluid mechanic conditions on the reactive uptake of ozone to five materials: two cellulose filter papers, two cementitious materials, and an activated carbon cloth. Results include (1) material porosity and pore size distributions, (2) effective diffusion coefficients for ozone in materials, and (3) material-ozone deposition velocities and reaction probabilities. At small length scales (0.02-0.16 cm) increasing thickness caused increases in estimated reaction probabilities from 1 × 10(-6) to 5 × 10(-6) for one type of filter paper and from 1 × 10(-6) to 1 × 10(-5) for a second type of filter paper, an effect not observed for materials tested at larger thicknesses. For high porosity materials, increasing chamber transport-limited deposition velocities resulted in increases in reaction probabilities by factors of 1.4-2.0. The impact of physical properties and transport effects on values of the Thiele modulus, ranging across all materials from 0.03 to 13, is discussed in terms of the challenges in estimating reaction probabilities to porous materials in scenarios relevant to indoor environments.

The spent liquor (SL) of a neutral sulfite semichemical pulping process contains lignocelluloses that are currently treated in a waste water system. In this work, an adsorption process using activated carbon (AC) was considered for isolating the lignin and hemicelluloses from SL. The maximum adsorptions of 0.9 g/g lignin and 0.43 g/g of hemicelluloses on AC were achieved under the conditions of 30 °C, pH 7 and 3 h with SL/AC weight ratio of 90. The addition of polydiallyldimethylammonium chloride (PDADMAC) to the SL/AC system significantly improved the adsorption of lignin to 2.5 g/g on AC. The molecular weight of PDADMAC considerably affected the results in that the higher MW PDADMAC led to less lignin, but more hemicelluloses, turbidity and chemical oxygen demand removals from the SL. The thermal analysis also revealed that the higher MW PDADMAC generated precipitates with a lower incineration temperature and heating value.

Activated carbon with large specific surface area and well-developed porosity was prepared from pyrolysis of K2CO3-impregnated lignin precipitated from reed pulp black liquors. The impregnation ratio was 1:1. The effect of activation temperature upon the Brunauer-Emmett-Teller (BET) specific surface area and pore volume of the carbon was closely investigated. Increasing activation temperature led to an opening and widening of the porous structure below 800'C. Above 800'C, the excess widening of pore led to the decrease of BET surface area and micropore volume. The BET surface area and pore volume of the carbon activated at 800 degrees C were 1395 m(2) g(-1) and 0.7702 ml g(-1) , respectively. The potential application of the carbon activated at 800 degrees C for removal of Cr (VI) was also investigated. The experimental results showed that it had good adsorption capacity.

Delayed petroleum coke, a waste by-product from the oil sand industry, was utilized in the production of activated carbon. The activated carbon was then evaluated for color and chlorinated organics reduction from pulp mill wastewater. The activation of the petroleum coke was evaluated using a fixed bed reactor involving carbonization and activation steps at temperature of 850 degrees C and using steam as the activation medium. The activation results showed that the maximum surface area of the activated coke was achieved at an activation period of 4 h. The maximum surface area occurred at burnoff and water efficiency of 48.5 and 54.3%, respectively. Increasing the activation period to 6 h resulted in a decrease in the surface area. Methylene blue adsorption results indicated that the activation process was successful. Methylene blue adsorbed per 100 g of applied activated coke was 10 times higher than that adsorbed by raw petroleum coke. Adsorption equilibrium results of the bleached wastewater and the activated coke showed that significant color, COD, DOC and AOX removal (90%) was achieved when the activated coke dose exceeded 15,000 mg/L. Adsorption isotherms, in terms of COD, DOC, UV and color were developed based on the batch equilibrium data. Based on these isotherms, the amount of activated coke required to achieve certain removal of color and AOX can be predicted. The utilization of the petroleum coke for the production of activated carbon can provide an excellent disposal option for the oil sand industry at the same time would provide a cheap and valuable activated carbon.