Secret History: Return of the Black Death Channel 4, 7-8pm In 1348 the Black Death swept through London, killing people within days of the appearance of their first symptoms. Exactly how many died, and why, has long been a mystery. This Secret History documentary follows experts as they pick through the evidence and reveal why the plague killed on such a scale. And they ask, what might be coming next?

Medscape

Biosorbents for heavy metals removal and their future

Microbial and plant derived biomass for removal of heavy metals from wastewater.

Heavy metal adsorbents prepared from the modification of cellulose : A review

Slow-pyrolysis of biomass for the production of biochar, a stable carbon-rich solid by-product, has gained considerable interest due to its proven role and application in the multidisciplinary areas of science and engineering. An alternative to slow-pyrolysis is a relatively new process called hydrothermal carbonization (HTC) of biomass, where the biomass is treated with hot compressed water instead of drying, has shown promising results. The HTC process offers several advantages over conventional dry-thermal pre-treatments like slow-pyrolysis in terms of improvements in the process performances and economic efficiency, especially its ability to process wet feedstock without pre-drying requirement. Char produced from both the processes exhibits significantly different physiochemical properties that affect their potential applications, which includes but is not limited to carbon sequestration, soil amelioration, bioenergy production, and wastewater pollution remediation. This paper provides an updated review on the fundamentals and reaction mechanisms of the slow-pyrolysis and HTC processes, identifies research gaps, and summarizes the physicochemical characteristics of chars for different applications in the industry. The literature reviewed in this study suggests that hydrochar (HTC char) is a valuable resource and is superior to biochar in certain ways. For example, it contains a reduced alkali and alkaline earth and heavy metal content, and an increased higher heating value compared to the biochar produced at the same operating process temperature. However, its effective utilization would require further experimental research and investigations in terms of feeding of biomass against pressure; effects and relationships among feedstocks compositions, hydrochar characteristics and process conditions; advancement in the production technique(s) for improvement in the physicochemical behavior of hydrochar; and development of a diverse range of processing options to produce hydrochar with characteristics required for various industry applications.

A comparative review of biochar and hydrochar in terms of production, physico-chemical properties and applications

Hydrothermal processing is an important thermochemical conversion process that is used to convert biomass into valuable products or biofuel. The process is usually performed in water at 250–374 °C under pressures of 4–22 MPa. The biomass is degraded into small components in water. Based on the target products, i.e., bio-oil, bio-gas or bio-carbon, the process conditions (temperature, pressure and time) are chosen. There has been significant effort in evaluating various biomass resources for hydrothermal processing because the process is suitable for any type of biomass including the co-utilization of biomass with waste materials. Additionally, because most biomass resources have high moisture contents, the most efficient way to process them is through hydrothermal processing. To understand hydrothermal biomass processing and the degradation pathway of biomass, it is necessary to understand the properties of water under hydrothermal conditions (i.e., subcritical and supercritical). In this respect, the physicochemical properties of water under subcritical and supercritical conditions and the interactions of water with biomass are discussed in the present paper. This review focuses on the hydrothermal processing of biomass and identifies the characteristics of various types of hydrothermal processing products. Additionally, this review provides an overview of the available biomass, the use of biomass as an energy source and related conversion technologies.

A review of hydrothermal biomass processing

Biosorption of heavy metal ions on immobilized white-rot fungus Trametes versicolor.

Biosorption of Hg2+, Cd2+, and Zn2+ by Ca-alginate and immobilized wood-rotting fungus Funalia trogii.

Entrapment of Lentinus sajor-caju into Ca-alginate gel beads for removal of Cd(II) ions from aqueous solution: preparation and biosorption kinetics analysis

In this study, cryogels containing imidazole functional groups were prepared by two different approaches and were used in the removal of Pb2+, Cd2+, Zn2+ and Cu2+ ions from aqueous solutions. In the first approach, poly(2-hydroxyethyl methacrylate-n-vinyl imidazole) [poly(HEMA-VIM)] cryogel was prepared using n-vinyl imidazole monomer. In the second approach, in order to increase the surface area, poly(HEMA-VIM)/poly(HEMA) composite cryogel was prepared by embedding the poly(HEMA-VIM) particles prepared with suspension polymerization into poly(2-hydroxyethyl methacrylate), poly(HEMA) cryogel. Both poly(HEMA-VIM)] cryogel and poly(HEMA-VIM)/poly(HEMA) composite cryogels were characterized by swelling studies, Fourier transform infrared spectroscopy, elemental analysis, surface area measurements and scanning electron microscopy. The surface area of poly(HEMA-VIM) cryogel was found to be 39.7 m2/g while the surface area of poly(HEMA-VIM)/poly(HEMA) composite cryogel was 78.6 m2/g as expected. The optimum adsorption conditions for metal uptake such as pH, metal ion concentration, and adsorption time were studied. Performed experiments showed that composite formation increased the adsorption capacity of the cryogel. The amounts of decreasing adsorption capacity were calculated as 38.5% for Cu2+, 39.1% for Pb2+, 66.9% for Zn2+ and 69.9% for Cd2+. The maximum adsorption capacities of the composite cryogel in the affinity order on mass basis were found to be Pb2+(7620 μg/g) > Cd2+(5800/μg) > Zn2+(4340 μg/g) > Cu2+(2540 μg/g) while on molar basis the order was Zn2+(66.4 μmol/g) > Cd2+(51.6 μmol/g) > Cu2+(40.0 μmol/g) > Pb2+(36.8 μmol/g). These results fitted well the Langmuir adsorption model. Competitive adsorption studies were performed with solutions containing the four heavy metal ions at 20 mg/L metal ion concentration. The binding capacities of the composite cryogel were found to be Pb2+(1498.2 μg/g) > Cu2+(742.5 μg/g) > Cd2+(550.4 μg/g) > Zn2+(450.5 μg/g) in competitive manner. It was observed that composite cryogels could be repeatedly used without significant loss in the adsorption capacity after ten repetitive adsorption–desorption processes.

Sema Bektaş

Papers

A review of hydrothermal biomass processing

Biosorption of heavy metal ions on immobilized white-rot fungus Trametes versicolor.

Biosorption of Hg2+, Cd2+, and Zn2+ by Ca-alginate and immobilized wood-rotting fungus Funalia trogii.

Entrapment of Lentinus sajor-caju into Ca-alginate gel beads for removal of Cd(II) ions from aqueous solution: preparation and biosorption kinetics analysis

Preparation and characterization of composite cryogels containing imidazole group and use in heavy metal removal