Fractionation of Heavy Metals in Multi-Contaminated Soil Treated with Biochar Using the Sequential Extraction Procedure.

Heavy metals (HMs) toxicity represents a global problem depending on the soil environment's geochemical forms. Biochar addition safely reduces HMs mobile forms, thus, reducing their toxicity to plants. While several studies have shown that biochar could significantly stabilize HMs in contaminated soils, the study of the relationship of soil properties to potential mechanisms still needs further clarification; hence the importance of assessing a naturally contaminated soil amended, in this case with Paulownia biochar (PB) and Bamboo biochar (BB) to fractionate Pb, Cd, Zn, and Cu using short sequential fractionation plans. The relationship of soil pH and organic matter and its effect on the redistribution of these metals were estimated. The results indicated that the acid-soluble metals decreased while the fraction bound to organic matter increased compared to untreated pots. The increase in the organic matter metal-bound was mostly at the expense of the decrease in the acid extractable and Fe/Mn bound ones. The highest application of PB increased the organically bound fraction of Pb, Cd, Zn, and Cu (62, 61, 34, and 61%, respectively), while the BB increased them (61, 49, 42, and 22%, respectively) over the control. Meanwhile, Fe/Mn oxides bound represents the large portion associated with zinc and copper. Concerning soil organic matter (SOM) and soil pH, as potential tools to reduce the risk of the target metals, a significant positive correlation was observed with acid-soluble extractable metal, while a negative correlation was obtained with organic matter-bound metal. The principal component analysis (PCA) shows that the total variance represents 89.7% for the TCPL-extractable and HMs forms and their relation to pH and SOM, which confirms the positive effect of the pH and SOM under PB and BB treatments on reducing the risk of the studied metals. The mobility and bioavailability of these metals and their geochemical forms widely varied according to pH, soil organic matter, biochar types, and application rates. As an environmentally friendly and economical material, biochar emphasizes its importance as a tool that makes the soil more suitable for safe cultivation in the short term and its long-term sustainability. This study proves that it reduces the mobility of HMs, their environmental risks and contributes to food safety. It also confirms that performing more controlled experiments, such as a pot, is a disciplined and effective way to assess the suitability of different types of biochar as soil modifications to restore HMs contaminated soil via controlling the mobilization of these minerals.

Multivariate analysis for FTIR in understanding treatment of used cooking oil using activated carbon prepared from olive stone.

In this study, activated carbons prepared from the green and black olive stone (green OSAC and black OSAC) were used as adsorbents to investigate their removal efficiencies for oxidation products and polar compounds from used sunflower and corn cooking oils. The degree of oxidation level and polar compounds were evaluated using Fourier transform infrared (FTIR) with the principal component analysis and ultra-performance liquid chromatography. Two FTIR absorption peaks were used for the oil evaluation, namely 3007-3009 cm-1, which is related to C-H symmetric stretching vibration of the cis double bonds, and ~1743 cm-1, which is related to = CH and ester carbonyl stretching vibration of the functional groups of the triglycerides, C = O. The principal component analysis results showed significant variations in the oxidation level of the sunflower and the corn oils occurred after consecutive heating and French fries frying for 10 days. The oxidation products that are adsorbed on the surface of the OSAC forms π-complexes with the C = C parts of the OSAC system. It can be concluded that the prepared adsorbents can be promising, efficient, economically effective, and environmentally friendly alternative adsorbents for oil treatment applications.

Ionisable emerging pharmaceutical adsorption onto microwave functionalised biochar derived from novel lignocellulosic waste biomass.

Functionalised biochar (WpOH) was prepared from wild plum kernels using simultaneous pyrolysis and microwave potassium hydroxide (KOH) functionalisation. This was then applied to the removal (from water) of an ionisable pharmaceutical - naproxen (NPX). Characterization of the WpOH was carried out using pHpzc, SEM/EDX, BET, FTIR, XRD, and the principle adsorption mechanisms were thoroughly studied. A pseudo-second order kinetic model best described the reaction kinetic behaviour, and the Langmuir isotherm provided the best fit to the results. The maximum adsorptive interaction (73.14 mg/g) occurred between pH 5 and 7 through electrostatic attraction (the main interaction mechanism) between the negatively charged NPX and the positively charged WpOH functional groups. In addition, hydrogen-bonding and electron-donor-acceptor (EDA) interactions were important. In a competitive study, using NPX and carbamazepine (a basic/amphoteric drug), the different nature/structure of the two compounds resulted in slight competitive adsorption. The results demonstrate the potential for wild plum kernel biochar to be used in the efficient removal of emerging contaminants such as pharmaceuticals from water.

Extractable pool of biochar controls on crop productivity rather than greenhouse gas emission from a rice paddy under rice-wheat rotation.

The role of extractable pool of biochar in crop productivity and soil greenhouse gas (GHGs) emission is not yet clear. In this study, two biochars with and without extraction was added to a paddy before rice transplantation at 20 t·ha-1. Crop yield, plant traits and greenhouse gas emission monitored throughout a rice-wheat rotation. Between the biochar treatments, changes in bulk density and microbial biomass carbon were insignificant. However, the increase in organic carbon was similar between maize and wheat biochars while higher under bulk wheat biochar than extracted one. The increase in available P and K was higher under wheat than maize biochar regardless of extraction. Moreover, the increase in plant traits and grain yield, in rice season only, was higher under bulk than extracted biochars. Yet, there was no difference in changes in GHGs emission between bulk and extracted biochars regardless of feedstock. Nevertheless, increased methane emission for rice season was lower under extracted biochars than bulk ones. Overall, crop productivity rather than GHGs emission was affected by treatment of extraction of biochars. Thus, use of unextracted biochar is recommended for improving soil crop productivity in the paddy soils.

The effects of autohydrolysis pretreatment on the structural characteristics, adsorptive and catalytic properties of the activated carbon prepared from Eucommia ulmoides Oliver based on a biorefinery process.

Eucommia ulmoides Oliver (EU) wood was consecutively treated by autohydrolysis pretreatment and chemical carbonization post-treatment based on a biorefinery process. Results showed that the optimal condition of the autohydrolysis pretreatment and carbonization process yielded 10.37kg xylooligosaccharides (XOS), 1.39kg degraded hemicellulosic products, 17.29kg other degraded products from hemicelluloses and 40.72kg activated carbon (SBET of 1534.06m2/g) from the 100kg raw materials. Simultaneously, 29.14kg gas products generated from the optimum integrated process was significantly lower than that from the direct carbonization process (68.84kg). Besides, the optimal activated carbon (AC170-1.0) also showed a moderate catalytic activity and high stability for hydrogen production by catalytic methane decomposition. Overall, the data presented indicated that the integrated process is an eco-friendly and efficient process to produce XOS and activated carbon, which is beneficial for value-added and industrial application of EU wood.

Preparation of activated carbon from corn cob and its adsorption behavior on Cr(VI) removal.

Operation experiments were conducted to optimize the preparation of activated carbons from corn cob. The Cr(VI) adsorption capacity of the produced activated carbons was also evaluated. The impact of the adsorbent dosage, contact time, initial solution pH and temperature was studied. The results showed that the produced corn cob activated carbon had a good Cr(VI) adsorptive capacity; the theoretical maximum adsorption was 34.48 mg g(-1) at 298 K. The Brunauer-Emmett-Teller and iodine adsorption value of the produced activated carbon could be 924.9 m(2) g(-1) and 1,188 mg g(-1), respectively. Under the initial Cr(VI) concentration of 10 mg L(-1) and the original solution pH of 5.8, an adsorption equilibrium was reached after 4 h, and Cr(VI) removal rate was from 78.9 to 100% with an adsorbent's dosage increased from 0.5 to 0.7 g L(-1). The kinetics and equilibrium data agreed well with the pseudo-second-order kinetics model and the Langmuir isotherm model. The equilibrium adsorption capacity improved with the increment of the temperature.

UV/TiO2 photocatalytic disinfection of carbon-bacteria complexes in activated carbon-filtered water: Laboratory and pilot-scale investigation.

The occurrence of carbon-bacteria complexes in activated carbon filtered water has posed a public health problem regarding the biological safety of drinking water. The application of combined process of ultraviolet radiation and nanostructure titanium dioxide (UV/TiO2) photocatalysis for the disinfection of carbon-bacteria complexes were assessed in this study. Results showed that a 1.07 Lg disinfection rate can be achieved using a UV dose of 20 mJ cm(-2), while the optimal UV intensity was 0.01 mW cm(-2). Particle sizes ≥8 µm decreased the disinfection efficiency, whereas variation in particle number in activated carbon-filtered water did not significantly affect the disinfection efficiency. Photoreactivation ratio was reduced from 12.07% to 1.69% when the UV dose was increased from 5 mJ cm(-2) to 20 mJ cm(-2). Laboratory and on-site pilot-scale experiments have demonstrated that UV/TiO2 photocatalytic disinfection technology is capable of controlling the risk posed by carbon-bacteria complexes and securing drinking water safety.

Pyrochars from bioenergy residue as novel bio-adsorbents for lignocellulosic hydrolysate detoxification.

The robust supramolecular structure of biomass often requires severe pretreatments conditions to produce soluble sugars. Nonetheless, these processes generate some inhibitory compounds (i.e. furans compounds and aliphatic acids) deriving mainly from sugars degradation. To avoid the inhibition of the biological process and to obtain satisfactory sugars conversion level into biofuels, a detoxification step is required. This study investigates the use of two pyrochars derived from solid anaerobic digestates for the detoxification of lignocellulosic hydrolysates. At a pyrochar concentration of 40gL(-1), more than 94% of 5-HMF and 99% of furfural were removed in the synthetic medium after 24h of contact time, whereas sugars concentration remained unchanged. Furfural was adsorbed faster than 5-HMF by both pyrochars and totally removed after 3h of contact. Finally, the two pyrochars were found efficient in the detoxification of corn stalks and Douglas fir wood chips hydrolysates without affecting the soluble sugars concentrations.

MALDI-TOF identification of Gram-negative bacteria directly from blood culture bottles containing charcoal: Sepsityper® kits versus centrifugation-filtration method.

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry has dramatically altered the way microbiology laboratories identify clinical isolates. Direct blood culture (BC) detection may be hampered, however, by the presence of charcoal in BC bottles currently in clinical use. This study evaluates an in-house process for extraction and MALDI-TOF identification of Gram-negative bacteria directly from BC bottles containing charcoal. Three hundred BC aliquots were extracted by a centrifugation-filtration method developed in our research laboratory with the first 96 samples processed in parallel using Sepsityper® kits. Controls were colonies from solid media with standard phenotypic and MALDI-TOF identification. The identification of Gram-negative bacteria was successful more often via the in-house method compared to Sepsityper® kits (94.7% versus 78.1%, P≤0.0001). Our in-house centrifugation-filtration method was further validated for isolation and identification of Gram-negative bacteria (95%; n=300) directly from BC bottles containing charcoal.

Nonactivated and activated biochar derived from bananas as alternative cathode catalyst in microbial fuel cells.

Nonactivated and activated biochars have been successfully prepared by bananas at different thermotreatment temperatures. The activated biochar generated at 900°C (Biochar-act900) exhibited improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances in alkaline media, in terms of the onset potential and generated current density. Rotating disk electron result shows that the average of 2.65 electrons per oxygen molecule was transferred during ORR of Biochar-act900. The highest power density of 528.2 mW/m(2) and the maximum stable voltage of 0.47 V were obtained by employing Biochar-act900 as cathode catalyst, which is comparable to the Pt/C cathode. Owning to these advantages, it is expected that the banana-derived biochar cathode can find application in microbial fuel cell systems.

Biochar from anaerobically digested sugarcane bagasse.

This study was designed to investigate the effect of anaerobic digestion on biochar produced from sugarcane bagasse. Sugarcane bagasse was anaerobically digested to produce methane. The digested residue and fresh bagasse was pyrolyzed separately into biochar at 600 degrees C in nitrogen environment. The digested bagasse biochar (DBC) and undigested bagasse biochar (BC) were characterized to determine their physicochemical properties. Although biochar was produced from the digested residue (18% by weight) and the raw bagasse (23%) at a similar rate, there were many physiochemical differences between them. Compared to BC, DBC had higher pH, surface area, cation exchange capacity (CEC), anion exchange capacity (AEC), hydrophobicity and more negative surface charge, all properties that are generally desirable for soil amelioration, contaminant remediation or wastewater treatment. Thus, these results suggest that the pyrolysis of anaerobic digestion residues to produce biochar may be an economically and environmentally beneficial use of agricultural wastes.

A process for the purification of organochlorine contaminated activated carbon: Sequential solvent purging and reductive dechlorination.

A system for the purification of organochlorine contaminated activated carbon is described. The system involves a continuous flow of aqueous ethanol to purge organochlorines from activated carbon. The organochlorine laden solvent is simultaneously treated with zero valent zinc as the bulk electron source, water as the proton source and the electron shuttle cyanocobalamin as a catalyst for reductive dechlorination. The system was characterised by performing batch reactions and extractions before being applied in a continuous flow system. In particular the ratio of water to ethanol in the system needed to be optimised. Water is needed for the reductive dechlorination reaction whilst it is not conducive to the extraction process. An 80% ethanolic solution was found to give optimal reductive dechlorination rates without compromising extraction of organochlorines from activated carbon. Of three electron shuttles evaluated cyanocobalamin was discovered to be the most relevant to the system with respect to reductive dechlorination rates and its ability to avoid absorption to activated carbon.

The identification of a human skull recovered from an eBay sale.

A human skull seized by the State of Louisiana from an eBay sale is analyzed. Bioarchaeological analyses of age-at-death, sex, and population affinity suggest the individual represented by the skull was a middle-aged Native American female. The presence of intentional cranial modification independently supports the population affinity assessment while confounding the metric analyses. However, no further specificity as to population affinity could be inferred using existing methods and comparative databases. Sedimentological and palynological analyses were attempted to redress this impasse. The presence of fine-grained charcoal, abundant fungal remains, and small angular quartz grains suggestive of burial in loess, as well as the lack of pollen, pteridophyte spores, and microscopic algae, suggest a likely upland burial location from somewhere in the lower Mississippi Valley. The sedimentological and palynological analyses, while not conclusive, show promise for use in future affiliation analyses of human remains recovered during the course of forensic investigations. The results are reviewed within the broader context of the legal debate over the repatriation of human remains.

Recovery of activated carbon catalyst, calcium, nitrogen and phosphate from effluent following supercritical water gasification of poultry manure.

A new method for suspending a fine, activated carbon catalyst in a biomass feedstock used for a supercritical water gasification (SCWG) continuous reactor is proposed. In a previous study, the organic matter in poultry manure was shown to be completely converted into gases such as H(2), CO(2) and CH(4) using SCWG. In practice, however, since the feedstock is not only composed of organic matter, but also contains inorganic material, water and catalyst, products such as gas, solid and liquid are produced during SCWG. The aim of this work was to investigate SCWG by-product utilization. This paper describes fundamental studies on the recovery of materials from SCWG products to develop a novel and simple recycling process that utilizes the by-products. A major portion of the activated carbon, monetite and ammonium sulfate can be isolated from the SCWG effluent.

Activated carbons from waste biomass: an alternative use for biodiesel production solid residues.

Defective coffee press cake, a residue from coffee oil biodiesel production, was evaluated as raw material for production of an adsorbent for removal of methylene blue (MB) from aqueous solution. Batch adsorption tests were performed at 25 degrees C and the effects of particle size, contact time, adsorbent dosage and pH were investigated. Preliminary adsorption tests indicated that thermal treatment is necessary in order to improve adsorption capacity. Adsorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, with the second-order model providing the best description of MB adsorption onto the prepared adsorbent. The experimental adsorption equilibrium data were fitted to Langmuir, Freundlich and Temkin adsorption models, with the last two providing the best fits. The experimental data obtained in the present study indicated that this type of waste material is a suitable candidate for use in the production of adsorbents for removal of cationic dyes, thus contributing for the implementation of sustainable development in both the coffee and biodiesel production chains.

Removal of pesticides from white wine by the use of fining agents and filtration.

The effects of four clarification agents (bentonite, charcoal, PVPP and potassium caseinate) on the removal of residues of three fungicides (famoxadone, fluquinconazole and trifloxystrobin) applied directly to a racked white wine, elaborated from Airen variety grapes from the D.O. Region of Jumilla (Murcia, Spain) are studied. The clarified wines were filtered with 0.45 microm nylon filters to determine the influence of this winemaking process in the disappearance of fungicide residues. Hydro-alcoholic solutions with the three fungicides at concentrations of 1 and 2 ppm were then added through intense stirring to each of the containers. Two hours later, the corresponding clarifying agent was added with intense stirring for some minutes. The containers were then sealed and left to settle for five days. Once the clean wines had been racked, they were filtered through nylon 0.45 microm pore filters. All assays were performed three times. Analytical determination of fluquinconazole and trifloxystrobin was performed by gas chromatography with an electron captor detector (ECD), while that of famoxadone was made using an HPLC-DAD. For the three fungicides, the highest elimination is produced with the clarification by charcoal, reaching Levels of removal of 100% in all cases. For the four clarifying agents, the highest elimination is produced for the fluquinconazole residues. The fungicide which is retained most in the lees is famoxadone, since it has the lowest solubility of the three pesticides studied. The highest percentage of residues in the lees is obtained for the assay with charcoal. The filtration process of the clarified wines using the four agents studied is not effective, since the elimination percentage is generally lower than 10% of the initial residues in the non-clarified wines.

Activated carbons from sewage sludge and discarded tyres: production and optimization.

This is a study about making use of two residual materials such as sludges from a sewage treatment plant and discarded tyres to generate activated carbons and later optimize the production process. H2SO4 and ZnCl2 were used as chemical activating agents. Liquid-phase adsorption tests were made using the produced carbons to retain methylene blue and iodine. The best precursor was sludge activated with ZnCl2. After optimization studies, the best production methodology involved a 1:1 ratio of sludge and ZnCl2, a heating rate of 5 degrees C/min up to 650 degrees C and a residence time of 5 min. The resulting materials adsorbed up to 139.4 mg/g of methylene blue and 1358.5 mg/g of iodine. Nevertheless these carbons may leach Zn while using. To avoid this two treatments were carried out: one consisting of a coating with a polymer and another involving an intensive washing, which was seen to be more efficient.

Evaluation of carcinogenic/co-carcinogenic activity of chikusaku-eki, a bamboo charcoal by-product used as a folk remedy, in BALB/c 3T3 cells.

Chikusaku-eki is an acidic dark brown liquid obtained as a by-product from bamboo charcoal burners. The solution diluted with water is gaining widespread popularity in Japan as a folk medicine for skin diseases such as scabies, eczema, and atopic dermatitis. In this study, the carcinogenic and tumor-promoting potential of chikusaku-eki was determined using the BALB/c 3T3 A31-1-1 cell transformation system. Carcinogenic activity was tested by treating A31-1-1 cells for 24 h with 0.06% solution, a dose resulting in 35% clonogenic cell survival. In both 2-O-tetradecanoylphorbol-13-acetate (TPA)-treated and non-treated groups, chikusaku-eki did not initiate carsinogenesis. Following initiation with 3-methylcholanthrene (3-MCA), A31-1-1 cells were chronically treated with a non-toxic concentration range of chikusaku-eki (< or = 0.01%), but chikusaku-eki did not act as a tumor promoter. Thus, chikusaku-eki was not carcinogenic/co-carcinogenic in the in vitro cell transformation assay examined in this study after being diluted more than 10(4)-fold with water.

Preparation of activated carbons from corn cob catalyzed by potassium salts and subsequent gasification with CO2.

In the present study, granular activated carbons were prepared from agricultural waste corn cob by chemical activation with potassium salts and/or physical activation with CO2. Under the experimental conditions investigated, potassium hydroxide (KOH) and potassium carbonate (K2CO3) were effective activating agents for chemical activation during a ramping period of 10 degrees C/min and subsequent gasification (i.e., physical activation) at a soaking period of 800 degrees C. Large BET surface areas (>1,600 m2/g) of activated carbons were thus obtained by the combined activation. In addition, this study clearly showed that the porosity created in the acid-unwashed carbon products is substantially lower than that of acid-washed carbon products due to potassium salts left in the pore structure.