Mechanistic insights into the (im)mobilization of arsenic, cadmium, lead, and zinc in a multi-contaminated soil treated with different biochars.

The effect and mechanistic evidence of biochar on the (im)mobilization of potentially toxic elements (PTEs) in multi-contaminated soils, with respect to the role of surface-functional groups and organic/inorganic compounds of biochar, are poorly understood. Herein, biochars produced from grass residues, rice straw, and wood were applied to a mining-soil contaminated with As, Cd, Pb, and Zn for 473-d. Biochars did not reduce the mobilization of Cd and Zn, whereas they simultaneously exhibited disparate effects on As and Pb mobilization.

Biochar-induced metal immobilization and soil biogeochemical process: An integrated mechanistic approach.

The nature of biochar-derived dissolved organic matter (DOM) has a crucial role in the interactions between biochar and metal immobilization, carbon dynamics, and microbial communities in soil. This study utilized excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC) modeling to provide mechanistic evidence of biochar-induced influences on main soil biogeochemical processes. Three biochars produced from rice straw, wood, and grass residues were added to sandy and sandy loam soils and incubated for 473 d.

Slow pyrolyzed biochars from crop residues for soil metal(loid) immobilization and microbial community abundance in contaminated agricultural soils.

This study evaluated the feasibility of using biochars produced from three types of crop residues for immobilizing Pb and As and their effects on the abundance of microbial community in contaminated lowland paddy (P-soil) and upland (U-soil) agricultural soils. Biochars were produced from umbrella tree [Maesopsis eminii] wood bark [WB], cocopeat [CP], and palm kernel shell [PKS] at 500 °C by slow pyrolysis at a heating rate of 10 °C min. Soils were incubated with 5% (w w) biochars at 25 °C and 70% water holding capacity for 45 d.

Experimental study of fry-drying and melting system for industrial wastewater sludge.

In South Korea, ocean dumping of organic sludges has been prohibited by the London Convention and by Korean regulations. Therefore, the Government of South Korea has sought an alternative process for the disposal of organic sludges. Recently, the combined fry-drying and melting system has been recognized as an efficient way to utilize the energy content of organic industrial sludge.

Hydrodeoxygenation of Guaiacol Over Pt/Al-SBA-15 Catalysts.

Upgrading of bio-oil through catalytic hydrodeoxygenation (HDO) reaction was investigated for guaiacol as a model compound. A batch reactor was used for the reaction condition of 40 bar and 250 degrees C. The target product was cyclohexane.

Effect of steam activation of biochar produced from a giant Miscanthus on copper sorption and toxicity.

This study aims to evaluate the physiochemical properties, sorption characteristics, and toxicity effects of biochar (BC) produced from Miscanthus sacchariflorus via slow pyrolysis at 500°C and its steam activation product (ABC). Although BC has a much lower surface area than ABC (181 and 322m(2)g(-1), respectively), the Cu sorption capacities of BC and ABC are not significantly different (p>0.05).

Slow pyrolysis of rice straw: analysis of products properties, carbon and energy yields.

Among many uses of rice straw, application of its biochar from pyrolysis to the soil is receiving greater interest for increased crop productivity and sequestration of CO2. This study investigated slow pyrolysis of rice straw at 300-700°C to characterize the yields and detailed composition of the biochar, bio-oil and non-condensable gases. Biochar was analyzed for pH, microscopic surface area and pore volume distribution.

Highly stretchable piezoelectric-pyroelectric hybrid nanogenerator.

A highly stretchable hybrid nanogenerator has been developed using a micro-patterned piezoelectric polymer P(VDF-TrFE), PDMS-CNT composite, and graphene nanosheets. Mechanical and thermal energies are simultaneously harvested from a single cell of the device. The hybrid nanogenerator exhibits high robustness behavior even after 30% stretching and generates very stable piezoelectric and pyroelectric power outputs due to micro-pattern designing.

Comparison of biochar properties from biomass residues produced by slow pyrolysis at 500°C.

Application of biochar from biomass pyrolysis to soil is gaining greater interest; this can ameliorate the soil quality, reduce fertilizer consumption, and sequestrate carbon. This study compares the characteristics of biochar produced by slow pyrolysis at 500°C for agricultural residues: sugarcane bagasse, cocopeat, paddy straw, palm kernel shell (PKS) and umbrella tree. In the biochar yield, the influence of the inert and lignin contents was significant.

Biodiesel production via the transesterification of soybean oil using waste starfish (Asterina pectinifera).

Calcined waste starfish was used as a base catalyst for the production of biodiesel from soybean oil for the first time. A batch reactor was used for the transesterification reaction. The thermal characteristics and crystal structures of the waste starfish were investigated by thermo-gravimetric analysis and X-ray diffraction.

Characterization of cadmium removal from aqueous solution by biochar produced from a giant Miscanthus at different pyrolytic temperatures.

The objective of this study was to investigate the feasibility of biochar for removing Cd from aqueous solution. Biochars were produced from a Miscanthus sacchariflorus via slow pyrolysis at 300, 400, 500 and 600°C. Higher pyrolytic temperature resulted in biochar with a higher aromatic structure and fewer polar functional groups.

Characteristics of biochar produced from slow pyrolysis of Geodae-Uksae 1.

This study investigated producing biochar from Geodae-Uksae 1 for soil applications to sequestrate carbon from the atmosphere and improve the productivity of crops. Using a lab-scale packed bed reactor, pyrolysis products of Geodae-Uksae 1 were produced over a temperature range of 300-700°C with a heating rate of 10°C/min. Pyrolysis at 500°C was found appropriate for biochar production considering the properties of char and the amount of heat required.

Ash deposit characterisation in a large-scale municipal waste-to-energy incineration plant.

The deposition of ash - combustion residues - on superheaters and heat exchanger surfaces reduce their efficiency; this phenomenon was investigated for a large-scale waste-to-energy incineration facility. Over a period of six months, ash samples were collected from the plant, which included the bottom ash and deposits from the superheater, as well as flyash from the convective heat exchanger, the economiser and fabric filters. These were analysed for particle size, unburned carbon, elemental composition and surface morphology.

The characteristics of bio-oil produced from the pyrolysis of three marine macroalgae.

The pyrolysis of two brown macroalgae (Undaria pinnatifida and Laminaria japonica) and one red macroalgae (Porphyra tenera) was investigated for the production of bio-oil within the temperature range of 300-600°C. Macroalgae differ from lignocellulosic land biomass in their constitutional compounds and high N, S and ash contents. The maximum production of bio-oil was achieved at 500°C, with yields between 37.

Potential of municipal solid waste for renewable energy production and reduction of greenhouse gas emissions in South Korea.

Energy from waste (EfW) for nonrecyclable wastes is a suitable method of waste management and is important for renewable energy production. South Korea currently recycles 57% of household waste and landfills 26%. The remaining 17% is incinerated, mainly for heat production.

Influence of operation variables on fast pyrolysis of Miscanthus sinensis var. purpurascens.

Fast pyrolysis of Miscanthus was investigated in a bench-scale fluidized bed reactor for production of bio-oil. Process conditions were varied for temperature (350-550 degrees C), particle size (0.3-1.

Clean bio-oil production from fast pyrolysis of sewage sludge: effects of reaction conditions and metal oxide catalysts.

Fast pyrolysis of sewage sludge was carried out under different reaction conditions, and its effects on bio-oil characteristics were studied. The effect of metal oxide catalysts on the removal of chlorine in the bio-oil was also investigated for four types of catalysts. The optimal pyrolysis temperature for bio-oil production was found to be 450 degrees C, while much smaller and larger feed sizes adversely influenced production.

Bio-oil production from fast pyrolysis of waste furniture sawdust in a fluidized bed.

The amount of waste furniture generated in Korea was over 2.4 million tons in the past 3 years, which can be used for renewable energy or fuel feedstock production. Fast pyrolysis is available for thermo-chemical conversion of the waste wood mostly into bio-oil.

The reuse of spent mushroom compost and coal tailings for energy recovery: comparison of thermal treatment technologies.

Thermal treatment technologies were compared to determine an appropriate method of recovering energy from two wastes - spent mushroom compost and coal tailings. The raw compost and pellets of these wastes were combusted in a fluidised-bed and a packed-bed, and contrasted to pyrolysis and gasification. Quantitative combustion parameters were compared to assess the differences in efficiency between the technologies.

Ignition and burning rates of segregated waste combustion in packed beds.

Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces.