Biochar modification to enhance sorption of inorganics from water

Renewable energy sources e.g. biofuels, are the focus of this century. Economically and environmental friendly production of such energies are the challenges that limit their usages. Microalgae is one of the most promising renewable feedstocks. However, economical production of microalgae lipid in large scales is conditioned by increasing the lipid content of potential strains without losing their growth rate or by enhancing both simultaneously. Major effort and advances in this area can be made through the environmental stresses. However, such stresses not only affect the lipid content and species growth (biomass productivity) but also lipid composition. This study provides a comprehensive review on lipid enhancement strategies through environmental stresses and the synergistic or antagonistic effects of those parameters on biomass productivity and the lipid composition. This study contains two main parts. In the first part, the cellular structure, taxonomic groups, lipid accumulation and lipid compositions of the most potential species for lipid production are investigated. In the second part, the effects of nitrogen deprivation, phosphorus deprivation, salinity stress, carbon source, metal ions, pH, temperature as the most important and applicable environmental parameters on lipid content, biomass productivity/growth rate and lipid composition are investigated.

Microalgae lipid and biomass for biofuel production: A comprehensive review on lipid enhancement strategies and their effects on fatty acid composition

Abstract Biochar is a solid by-product of thermochemical conversion of biomass to bio-oil and syngas. It has a carbonaceous skeleton, a small amount of heteroatom functional groups, mineral matter, and water. Biochar’s unique physicochemical structures lead to many valuable properties of important technological applications, including its sorption capacity. Indeed, biochar’s wide range of applications include carbon sequestration, reduction in greenhouse gas emissions, waste management, renewable energy generation, soil amendment, and environmental remediation. Aside from these applications, new scientific insights and technological concepts have continued to emerge in the last decade. Consequently, a systematic update of current knowledge regarding the complex nature of biochar, the scientific and technological impacts, and operational costs of different activation strategies are highly desirable for transforming biochar applications into industrial scales. This communication presents a comprehensive review of physical activation/modification strategies and their effects on the physicochemical properties of biochar and its applications in environment-related fields. Physical activation applied to the activation of biochar is discussed under three different categories: I) gaseous modification by steam, carbon dioxide, air, or ozone; II) thermal modification by conventional heating and microwave irradiation; and III) recently developed modification methods using ultrasound waves, plasma, and electrochemical methods. The activation results are discussed in terms of different physicochemical properties of biochar, such as surface area; micropore, mesopore, and total pore volume; surface functionality; burn-off; ash content; organic compound content; polarity; and aromaticity index. Due to the rapid increase in the application of biochar as adsorbents, the synergistic and antagonistic effects of activation processes on the desired application are also covered.

A comprehensive review on physical activation of biochar for energy and environmental applications

Remediation of cadmium and lead polluted soil using thiol-modified biochar.

Biochar is the carbon-rich product obtained from the thermochemical conversion of biomass under oxygen-limited conditions. Biochar has attained extensive attention due to its agronomical and environmental benefits in agro-ecosystems. This work adopts the scientometric analysis method to assess the development trends of biochar research based on the literature data retrieved from the Web of Science over the period of 1998–2018. By analysing the basic characteristics of 6934 publications, we found that the number of publications grew rapidly since 2010. Based on a keyword analysis, it is concluded that scholars have had a fundamental recognition of biochar and preliminarily found that biochar application had agronomic and environmental benefits during the period of 1998–2010. The clustering results of keywords in documents published during 2011–2015 showed that the main research hotspots were “biochar production”, “biochar and global climate change”, “soil quality and plant growth”, “organic pollutants removal”, and “heavy metals immobilization”. While in 2016–2018, beside these five main research hotspots, “biochar and composting” topic had also received greater attention, indicating that biochar utilization in organic solid waste composting is the current research hotspot. Moreover, updated reactors (e.g., microwave reactor, fixed-bed reactor, screw-feeding reactor, bubbling fluidized bed reactor, etc.) or technologies (e.g., solar pyrolysis, Thermo-Catalytic Reforming process, liquefaction technology, etc.) applied for efficient energy production and modified biochar for environmental remediation have been extensively studied recently. The findings may help the new researchers to seize the research frontier in the biochar field.

A scientometric review of biochar research in the past 20 years (1998–2018)

Study on the effects of oxygen-containing functional groups on Hg0 adsorption in simulated flue gas by XAFS and XPS analysis.

Surface modification of bio-char by dielectric barrier discharge plasma for Hg0 removal

Preparation and characterization of benzoic acid-modified activated carbon for removal of gaseous mercury chloride

Effects of flue gas components on the oxidation of gaseous Hg0 by dielectric barrier discharge plasma

The non-thermal plasma injection method was used to oxidize elemental mercury (Hg0) in this study. A mixture of water vapor and oxygen was selected as the discharge gases. Active species generated by a dielectric barrier discharge plasma reactor were introduced into the flue gas duct, where they reacted with Hg0. Different parameters including active particles, supply voltage, flow rate of injection gas, system temperature, and typical flue gas components were considered. Experimental results indicated that it produced a high yield of oxidative species than using a single discharge gas, and the reason was believed to be the dissociation and excitation of water molecules and oxygen molecules by electron impact. It was assumed that active radicals include O, O3, water cluster ions (O2+·H2O), and ·OH. Increasing the plasma injection volume led to higher content of reactive species in the system, which promoted Hg0 oxidation. Approximately 98.3% of Hg0 was oxidized at 4 kV of voltage with 20 mL/min of plasma ...

Qiang Niu

Papers

Study on the effects of oxygen-containing functional groups on Hg0 adsorption in simulated flue gas by XAFS and XPS analysis.

Surface modification of bio-char by dielectric barrier discharge plasma for Hg0 removal

Preparation and characterization of benzoic acid-modified activated carbon for removal of gaseous mercury chloride

Effects of flue gas components on the oxidation of gaseous Hg0 by dielectric barrier discharge plasma

Investigation of Gaseous Elemental Mercury Oxidation by Non-thermal Plasma Injection Method