Occurrence, distribution, and toxicity assessment of polycyclic aromatic hydrocarbons in biochar, biocrude, and biogas obtained from pyrolysis of agricultural residues.

Occurrence, distribution, and toxicity assessment of polycyclic aromatic hydrocarbons (PAHs) in pyrolysis steams (biochar, biocrude, and biogas) of three agricultural residues was investigated at pyrolysis temperatures of 400-800 °C. Increasing PAHs formation was observed in the narrow temperature range (500-600 °C) in all feedstocks due to temperature-induced dehydration, decarboxylation, and dehydrogenation reactions. Low molecular weight PAHs (naphthalene, phenanthrene) were dominant in all product streams while high molecular weight PAHs were found in negligible concentrations.

Stabilization and solidification of arsenic and iron contaminated canola meal biochar using chemically modified phosphate binders.

Adsorption is a widely used process for removal of heavy metals, but the management of spent adsorbent containing concentrated amounts of heavy metals is a problem due to potential risk of groundwater contamination from leaching of heavy metals. Generally, cementitious binder and additives are used for stabilization and solidification treatment, however heavy metals tend to leach from such matrices. Therefore, this research investigated the effectiveness of chemically modified phosphate biochar (CMPB) composite for the simultaneous solidification and stabilization of arsenic (As) and iron (Fe) contaminated canola meal biochar.

Activity and stability of biochar in hydrogen peroxide based oxidation system for degradation of naphthenic acid.

This study investigated the stability and catalytic activity of wheat straw biochar (WS), hardwood biochar (HW) and commercial activated carbon (AC) in hydrogen peroxide (HO) based oxidation system for degradation of model naphthenic acids compound, 1-methyl-1- cyclohexane carboxylic acid (MCCA). WS showed excellent catalytic activity for decomposition of HO and MCCA degradation as demonstrated by high HO decomposition rate (2.0*10 Ms), amount of hydroxyl (OH) radicals generated (182 mg/L) and degradation efficiency of MCCA (100% at C - 100 mg/L).

Utilization of sludge based adsorbents for the removal of various pollutants: A review.

Sludge based adsorbents are widely used for the removal of various pollutants from water and wastewater systems and the available data is much diversified. The purpose of this review is to organize and critically review the scattered available information on the potential of use of sludge based adsorbents for the removal of various pollutants. It was observed that performance of the sludge based adsorbents varies depending on the type of pollutants, type of precursor sludge, carbonization time-temperature profile and the type of activation conditions used.

Risk assessment and technical feasibility of usage of paper mill sludge biochar-based exhausted adsorbent for geopolymeric brick formation.

Risk assessment and technical feasibility of brick formation from exhausted paper mill sludge derived biochar obtained after its use as an adsorbent for the treatment of effluent containing pentachlorophenol was studied. The bricks were prepared by geopolymerization mechanism in presence of sodium hydroxide, and the extent of geopolymerization was determined on the basis of crystal structure, surface functionalities, and surface morphology of the bricks. The preparation parameters (sodium hydroxide dosage, initial water and calcium carbonate content and curing temperature) were optimized and the results were analyzed in terms of compressive strength, water absorption, and abrasion index.

In-situ chemical oxidation: Principle and applications of peroxide and persulfate treatments in wastewater systems.

Hydrogen peroxide (H2O2) and persulfate are the most efficient and commonly used oxidants in in-situ chemical oxidation (ISCO) of organic contaminants. This review focuses on the principle and activation techniques used in H2O2 and persulfate based ISCO processes. It is crucial to understand the effect of activation techniques on process chemistry and free radicals behaviour in order to achieve high degradation efficiency.

Heavy metal content in various types of candies and their daily dietary intake by children.

Children are vulnerable to heavy metal contamination through consumption of candies and chocolates. Considering this representative samples (69) of candies and chocolates based on cocoa, milk and sugar were analyzed for selected heavy metals by means of flame atomic absorption spectrometry. The average concentration of Zn, Pb, Ni, and Cd was found to be 2.

Effect of pyrolysis temperature on polycyclic aromatic hydrocarbons toxicity and sorption behaviour of biochars prepared by pyrolysis of paper mill effluent treatment plant sludge.

The polycyclic aromatic hydrocarbons (PAHs) toxicity and sorption behaviour of biochars prepared from pyrolysis of paper mill effluent treatment plant (ETP) sludge in temperature range 200-700 °C was studied. The sorption behaviour was found to depend on the degree of carbonization where the fractions of carbonized and uncarbonized organic content in the biochar act as an adsorption media and partition media, respectively. The sorption and partition fractions were quantified by isotherm separation method and isotherm parameters were correlated with biochar properties (aromaticity, polarity, surface area, pore volume and ash content).

Synthesis of the magnetic biochar composites for use as an adsorbent for the removal of pentachlorophenol from the effluent.

The zero-valent iron magnetic biochar composites (ZVI-MBC) were synthesized from the paper mill sludge biochar and used for the treatment of the synthetic and real effluent containing pentachlorophenol (PCP). During the synthesis of ZVI-MBC, NaBH4 was used as the reducing agent to reduce Fe(II) to Fe(0) and cetyltrimethylammonium bromide was added as surfactant. The effect of the molar ratio of FeSO4 to NaBH4, dose of the surfactant and the ZVI to biochar ratio on the PCP removal efficiency was investigated.

Risk analysis of pyrolyzed biochar made from paper mill effluent treatment plant sludge for bioavailability and eco-toxicity of heavy metals.

The risk analysis was performed to study the bioavailability and eco-toxicity of heavy metals in biochar obtained from pyrolysis of sludge of pulp and paper mill effluent treatment plant. The sludge was pyrolyzed at different temperatures (200-700°C) and the resultant biochar were analyzed for fractionation of heavy metals by sequential extraction procedure. It was observed that all the heavy metals get enriched in biochar matrix after pyrolysis, but the bioavailability and eco-toxicity of the heavy metals in biochar were significantly reduced as the mobile and bioavailable heavy metal fractions were transformed into the relatively stable fractions.