Removal of trivalent samarium from aqueous solutions by activated biochar derived from cactus fibres

The efficiency of activated biochar fibres obtained from Opuntia Ficus lndica regarding me sorpuon oi trlvalent samarium （Sm（Ⅲ）） from aqueous solutions was investigated by batch experiments. The effect of various physicochemical parameters （e.g. pH, initial metal concentration, ionic strength, temperature and contact time） on the Sm（III） adsorption was studied and the surface species were characterized by FTIR spectroscopy prior to and after the lanthanide sorption. The experimental results showed that the acti- vated biochar fibres possessed extraordinary sorption capacity for Sm（Ⅲ） in acidic solutions （qmax=90 g/kg, pH 3.0） and near neutral solutions （qmax=350 g/kg, pH 6.5）, This was attributed to the formation of samarium complexes with the surface carboxylic moieties, available in high density on the lamellar structures of the bio-sorbent.

Microwave physicochemical activation:an advanced approach to produce activated biochar for palm oil mill effluent treatment

Empty fruit bunch(EFB)is an industrial waste that is abundantly available in Malaysia.Traditionally,EFBs were burned and dumped on the plantation site,resulting in global warming pollution from methane and carbon dioxide.In this study,the EFB was transformed into a high-surface area of activated biochar through a microwave physicochemical approach involving the combination of steam followed by a hydroxide mixture for palm oil mill effluent(POME)treatment.It was found that BET(Brunauer-Emmett-Teller)surface area and total pore volume of activated biochar were 365.60 m^(2)/g and 0.16 cm^(3)/g,respectively.The surface morphology of activated biochar revealed the formation of well-developed pores that can potentially be used as adsorbents to treat POME.The removal efficiency of biochemical oxygen demand(BOD)and chemical oxygen demand(COD)of POME achieved 75%-55%,respectively.This study offers insight into the transformation of industrial waste into value-added products for sustainable environmental remediation.

Naturally Nitrogen-Doped Biochar Made from End-of-Life Wood Panels for SO_(2) Gas Depollution

Reconstituted wood panels have several advantages in terms of ease of manufacturing,but their shorter life span results in a huge amount of reconstituted wood panels being discarded in sorting centers yearly.Currently,the most common approach for dealing with this waste is incineration.In this study,reconstituted wood panels were converted into activated biochar through a two-step thermochemical process:(i)biochar production using pilot scale fast pyrolysis at 250 kg/h and 450℃;and(ii)a physical activation at three temperatures(750℃,850℃ and 950℃)using an in-house activation furnace(1 kg/h).Results showed that the first stage removed about 66% of the nitrogen from the wood panels in the form of NO,NH3,and trimethylamine,which were detected in small amounts compared to emitted CO_(2).Compared to other types of thermochemical conversion methods(e.g.,slow pyrolysis),isocyanic acid and hydrogen cyanide were not detected in this study.The second stage produced activated biochar with a specific surface area of up to 865 m^(2)/g at 950℃.The volatile gases generated during activation were predominantly composed of toluene and benzene.This two-step process resulted in nitrogen-rich carbon in the form of pyrrolic and pyridinic nitrogen.Activated biochars were then evaluated for their SO_(2) retention performance and showed an excellent adsorption capacity of up to 2140 mg/g compared to 65 mg/g for a commercial activated carbon(889 m^(2)/g).End-of-life reconstituted wood panels and SO_(2) gas are problematic issues in Canada where the economy largely revolves around forestry and mining industries.

Breakthrough CO_2 adsorption in bio-based activated carbons

In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO2 activation and Potassium hydroxide（KOH） activation. CO2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO2 concentration range of10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N2 and CO2 adsorption at 77 and 273 K, respectively.Central composite design was used to evaluate the combined effects of temperature and concentration of CO2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm3/g and surface area of 1400 m2/g had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO2 and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO2 activated carbons remained remarkably stable after50 cycles with low temperature（160°C） regeneration.

Biochar insights from laboratory incubations monitoring O_(2) consumption and CO_(2) production

Biochar has been touted as a long-term carbon sequestration tool.However,there are no studies evaluating biochar’s effect on oxygen(O_(2))consumption as a measure of the microbial respiration response to biochar.To gain insight into this aspect,we evaluated O_(2) consumption rates to test the hypothesis that biochar is an efficient agent for carbon dioxide(CO_(2))sequestration in soils.Four different biochar types and one activated charcoal were incubated alone and associated with three different soils for approximately 2 months in laboratory incubations.Headspace concentration of CO_(2) and O_(2) was periodically quantified.The data presented here confirm that the CO_(2) production following biochar’s addition to soils results in a process that is correlated to oxygen consumption.However,this overall stimulation is not clearly related to biochar type.Activated carbon resulted in the highest statistically significant stimulation of activity,despite it possessing the lowest quantity of volatile carbon and mineral nutrient sources.Taking into consideration our results,we conclude that using biochar does achieve total carbon sequestration.However,the amount of available soil organic carbon following soil incorporation appears to be reduced following biochar addition and its long-term implication on this mineralizable soil organic carbon pool does deserve more research attention.