Adsorption Capability Of Biochar Research Articles

Preparation of highly adsorptive biochar by sequential iron impregnation under refluxing and pyrolysis at low temperature for removal of tetracycline

Iron-doping modification is a prevailing approach for improving adsorption capability of biochar with environmental friendliness, but usually requires high temperature and suffers from iron aggregation. Herein, a highly adsorptive biochar was manufactured via sequential disperse impregnation of iron by refluxing and pyrolysis at low temperature for eliminating tetracycline (TC) from aqueous solution. Iron oxides and hydroxides were impregnated and stably dispersed on the carbon matrix as pyrolyzed at 200 °C, meanwhile abundant oxygen and nitrogen functional groups were generated on surface. The iron-doped biochar exhibited up to 891.37 mg/g adsorption capacity at pH 5, and could be recycled with high adsorption capability. The adsorption of TC should be mostly contributed to the hydrogen bonding of N/O functional groups and the hydrogen bonding/coordination of iron oxides/hydroxides. This would provide a valuable guide for dispersedly doping iron and conserving functional groups on biochar, and a super iron-doped biochar was prepared with superior recyclability.

ความสามารถในการดูดซับก๊าซไฮโดรเจนซัลไฟด์ของถ่านชีวภาพที่ผลิตจากชีวมวลเหลือใช้

ความสามารถในการดูดซับก๊าซไฮโดรเจนซัลไฟด์ของถ่านชีวภาพที่ผลิตจากชีวมวลเหลือใช้

Adsorption of Lead from Aqueous Solution by Biochar: A Review

Industrialization has resulted in the discharge of a certain amount of lead (Pb) from industrial sources causing damage risk to water quality and human health. Adsorption is an effective technique to remove Pb, and biochar has been widely studied owing to its advantages of low cost and high adsorption capacity. This review summarizes the influence of raw materials and modification methods on the adsorption capability of biochar. The adsorption isotherms and kinetics of biochar were summarized, and the main Pb removal mechanisms were studied systematically. In addition, the challenges and future perspectives were discussed comprehensively. It is expected that the review could provide insightful fundamentals for the experimental research and practical applications of biochar.

Addition of biochar as thin preamble layer into sand filtration columns could improve the microplastics removal from water

The release of microplastics (MPs) especially those with sizes less than 10 μm from effluent of wastewater treatment plants (WWTPs) is one of the major sources of plastics into aquatic environment. To reduce the discharge of MPs into environment, it is essential to further enhance their removal efficiencies in WWTPs. In present study, to boost the removal performance of MPs in sand filtration systems (units that commonly employed in WWTPs to remove colloidal pollutants), six types of biochar fabricated from three raw biomass materials (i.e. lignin, cellulose, and woodchips) at two pyrolysis temperatures (400 °C and 700 °C) was respectively amended into sand columns as thin permeable layer. We found that adding all six types of biochar into sand columns as thin permeable layer could greatly improve the retention of MPs with the diameter of 1 μm under either slow (4 m/d) or fast flow rates (160 m/d) due to the high adsorption capability of biochar. Woodchip-derived biochar exhibited the highest MPs retention performance, which was followed by cellulose-derived biochar and then lignin-derived biochar. Moreover, for biochar derived from three raw biomasses, increasing pyrolysis temperature could improve MPs retention performance. The direct observation of real-time plastics retention processes on different types of biochar via a visible flow chamber showed that woodchip-derived biochar especially that fabricated at 700 °C exhibited more MPs trapping processes relative to lignin and cellulose-derived biochar due to their more complex surface morphology. Thus, the highest MPs retention performance was achieved in sand columns with amendment by 1 wt% woodchip-derived biochar fabricated at 700 °C. More importantly, we found that for these modified sand filtration column systems, complete MPs removal could be achieved in real river water and actual sewage water, in multiple filtration cycles, longtime filtration process (100 pore volumes injection) as well as with interval flow conditions. Moreover, biochar could be regenerated and reused as thin permeable layer to effectively remove MPs. The results of this study clearly showed that biochar especially woodchip-derived biochar fabricated at 700 °C had the potential to immobilize MPs especially those with small sizes in WWTPs.

Unravelling the Environmental Application of Biochar as Low-Cost Biosorbent: A Review

In this age, a key target for enhancing the competitiveness of the chemical, environmental and biotechnology industries is to manufacture high-value products more efficiently and especially with significantly reduced environmental impact. Under this premise, the conversion of biomass waste to a high-value added product, biochar, is an interesting approach under the circular economy principles. Thus, the improvements in the biochar production and its new and innovative uses are hot points of interest, which are the focus of vast efforts of the scientific community. Biochar has been recognized as a material of great potential, and its use as an adsorbent is becoming a reliable strategy for the removal of pollutants of different streams, according to its high adsorption capacity and potential to eliminate recalcitrant compounds. In this review, a succinct overview of current actions developed to improve the adsorption capability of biochar, mainly of heavy metal and organic pollutants (dyes, pharmaceuticals and personal care products), is summarized and discussed, and the principal adsorption mechanisms are described. The feedstock and the production procedure are revealed as key factors that provide the appropriate physicochemical characteristics for the good performance of biochar as an adsorbent. In addition, the modification of the biochar by the different described approaches proved their feasibility and became a good strategy for the design of selective adsorbents. In the last part of this review, the novel prospects in the regeneration of the biochar are presented in order to achieve a clean technology for alleviating the water pollution challenge.

Using corncob-based biochar to intercept BTEX in stormwater filtration systems.

A biochar material made from corncobs was tested for its capability in BTEX adsorption/interception in stormwater filtration systems. Batch experiments were conducted to examine the adsorption kinetics, adsorption isotherms, and adsorption thermodynamics of BTEX onto this biochar. The feasibility of applying this biochar in stormwater filtration was studied by dynamic transport experiments and model simulations. The result showed that this biochar can adsorb BTEX and the adsorption is a thermodynamically spontaneous, and endothermic process. The BTEX adsorption kinetic experiment and adsorption retarded BTEX transport experiment indicated that the BTEX adsorption kinetics can be changed by the driving force between the BTEX concentrations and the active adsorption site as well as the contact time between BTEX and the biochar. In terms of applying this biochar in stormwater filtration, the Monte Carlo uncertainty analysis indicated that the BTEX interception is sensitive to the hydraulic conductivity of the biochar filter and the adsorption kinetics of the biochar material. Although this corncob-made biochar demonstrated effective pollutant adsorption capability, the biochar adsorption capability should be utilized to retain the pollutant long enough for biodegradation to take effect for ultimate pollutant attenuation.

Influence of Pyrolysis Temperature on Characteristics and Nitrobenzene Adsorption Capability of Biochar Derived from Reed and Giant Reed

Influence of Pyrolysis Temperature on Characteristics and Nitrobenzene Adsorption Capability of Biochar Derived from Reed and Giant Reed

A modified method for enhancing adsorption capability of banana pseudostem biochar towards methylene blue at low temperature

A phosphomolybdic acid promoted oxidative pyrolysis was described for preparation of banana pseudostem biochar. The strategy succeeded to introduce oxygen-containing groups onto the biochar surface at low temperature. In addition, pore channels were created, demonstrated by the SEM images of biochar prepared at 200 °C. Adsorption experiments showed that the biochar pyrolyzed at 200 °C exhibited much better adsorption capability than others pyrolyzed at higher temperatures for methylene blue (MB). The adsorption capability of biochar prepared at 200 °C was enhanced from 87.28 to 146.23 mg/g at 45 °C with phosphomolybdic acid modification. The enhancement of adsorption capacity could be ascribed to the increase of surface oxygen-containing functional groups and pore channels. In-situ generated carboxylic groups during adsorption and desorption played an important role in removal of MB. Adsorption of MB was mainly attributed to hydrogen bonding, electrostatic interactions and cation exchanges.

Use of carbon dioxide as a reaction medium in the thermo-chemical process for the enhanced generation of syngas and tuning adsorption ability of biochar

This study mechanistically investigated the influences of CO2 on syngas (H2 and CO) production during thermo-chemical conversion of red seaweed, and further explored the possible utility of the produced biochar as a medium for adsorption of inorganic/organic contaminants in aqueous phase. In order to elucidate the key roles of CO2 in the thermo-chemical process, the composition analysis of syngas and the qualitative analysis of pyrolytic oil were conducted and compared with those in pyrolysis in N2 condition. Pyrolysis of red seaweed in the presence of CO2 led to the enhanced generation of syngas at the entire experimental temperatures. For example, the ratio of CO to H2 in the presence of CO2 at 620°C was enhanced by ∼400%, as compared to the case in N2. This enhanced generation of syngas resulted in significant pyrolytic oil reduction by ∼70% at 620°C via the unknown reactions between VOCs and CO2. In addition, biochar generated in the CO2 environment exhibited comparatively higher surface area (61m2g−1) and more porous structure. The morphological modification induced by CO2 provided the favorable condition for removal of methylene blue from the aqueous phase. Thus, this study experimentally demonstrated that exploiting CO2 as a reaction medium would provide an attractive option for the enhanced generation of syngas and the tuned adsorption capability of biochar.

Influence of pyrolysis temperature on characteristics and phosphate adsorption capability of biochar derived from waste-marine macroalgae (Undaria pinnatifida roots)

The collected roots of Undaria pinnatifida, the main waste in farming sites, accounting for 40–60% of annual production, was pyrolyzed under temperature ranging from 200 to 800°C to evaluate the influence of pyrolysis temperature on biochar properties and phosphate adsorption capacity. It was confirmed that an increase in the pyrolysis temperature led to a decrease of the yield of biochar, while ash content remained almost due to carbonization followed by mineralization. Elemental analysis results indicated an increase in aromaticity and decreased polarity at a high pyrolysis temperature. When the pyrolysis temperature was increased up to 400°C, the phosphate adsorption capacity was enhanced, while a further increase in the pyrolysis temperature lowered the adsorption capacity due to blocked pores in the biochar during pyrolysis. Finally, a pot experiment revealed that biochar derived from waste-marine macroalgae is a potent and eco-friendly alternative material for fertilizer after phosphate adsorption.

Biochar Mitigates Salinity Stress in Potato

AbstractA pot experiment was conducted in a climate‐controlled greenhouse to investigate the growth, physiology and yield of potato in response to salinity stress under biochar amendment. It was hypothesized that addition of biochar may improve plant growth and yield by mitigating the negative effect of salinity through its high sorption ability. From tuber bulking to harvesting, the plants were exposed to three saline irrigations, that is 0, 25 and 50 mm NaCl solutions, respectively, and two levels of biochar (0 % and 5 % W/W) treatments. An adsorption study was also conducted to study the Na+ adsorption capability of biochar. Results indicated that biochar was capable to ameliorate salinity stress by adsorbing Na+. Increasing salinity level resulted in significant reductions of shoot biomass, root length and volume, tuber yield, photosynthetic rate (An), stomatal conductance (gs), midday leaf water potential, but increased abscisic acid (ABA) concentration in both leaf and xylem sap. At each salinity level, incorporation of biochar increased shoot biomass, root length and volume, tuber yield, An, gs, midday leaf water potential, and decreased ABA concentration in the leaf and xylem sap as compared with the respective non‐biochar control. Decreased Na+, Na+/K+ ratio and increased K+ content in xylem with biochar amendment also indicated its ameliorative effects on potato plants in response to salinity stress. The results suggested that incorporation of biochar might be a promising approach for enhancing crop productivity in salt‐affected soils.