A review on heavy metal pollution, toxicity and remedial measures: Current trends and future perspectives

An overview of carbothermal synthesis of metal–biochar composites for the removal of oxyanion contaminants from aqueous solution

The MgAl-layered double hydroxide (LDH) was modified with polyethylene polyamine (PP) and tannic acid (TA) to improve the adsorption property of heavy metal ions. The PP@TA encapsulated LDH (denoted as LDH-PP@TA) was prepared via the combination of catechol chemistry and Michael addition and/or Schiff base reaction and characterized through TEM, FT-IR, SEM, TGA, and XPS. The adsorption performance was investigated by using LDH-PP@TA as adsorbent to adsorb the copper (II) ions from aqueous solution. The effect of contact time, solution pH, initial copper (II) ions concentration and temperature were investigated. The LDH-PP@TA exhibited high adsorption capacity of 41.56 mg/g, which is almost double that by LDH (23.39 mg/g). Equilibrium data for adsorption of copper (II) ions on adsorbents could be well fitted by the pseudo-second-order and Langmuir equations. Thermodynamic studies show the adsorption process is spontaneous and endothermic. Electrostatic adhesion and formation of copper complex are the major mechanisms for the copper (II) ions removal by LDH-PP@TA. These results reveal the great potential of LDH-PP@TA in the application of heavy metal ions removal.

Preparation of polyethylene polyamine@tannic acid encapsulated MgAl-layered double hydroxide for the efficient removal of copper (II) ions from aqueous solution

Critical review of magnetic biosorbents: Their preparation, application, and regeneration for wastewater treatment.

Agricultural waste management strategies for environmental sustainability.

This paper discusses the synthesis of magnetic adsorbents from agricultural waste and their applications in heavy metals removal. The general methods for preparing magnetic adsorbents and the mechanisms of heavy metal sorption are also reviewed in detail. These mechanisms are related to the utilization of magnetic adsorbents, particularly sugarcane bagasse in heavy metals removal, such as nickel, cadmium, lead, and arsenic. Converting sugarcane bagasse into magnetic adsorbents could solve environmental problems, such as agricultural waste and water pollution. A brief summary of the synthesis of magnetic biochar from sugarcane bagasse and its applications in heavy metals removal is also presented. Thus, this study proposes magnetic-based materials as potential candidates for wastewater treatment, and this adds new dimensions to numerous applications of the carbon family.

Agricultural biomass-derived magnetic adsorbents: Preparation and application for heavy metals removal

The present work describes a self-sustaining bioelectrochemical system that adopts simple cell configurations and operates in uncontrolled ambient surroundings. The microbial fuel cell (MFC) was comprised of white-rot fungus of Phanaerochaete chrysosporium fed with oil palm empty fruit bunch (EFB) as the substrate. This fungal strain degrades lignin by producing ligninolytic enzymes such as laccase, which demonstrates a specific affinity for oxygen as its electron acceptor. By simply pairing zinc and the air electrode in a membraneless, single-chamber, 250-mL enclosure, electricity could be harvested. The microbial zinc/air cell is capable of sustaining a 1 mA discharge current continuously for 44 days (i.e., discharge capacity of 1056 mAh). The role of the metabolic activities of P. chrysosporium on EFB towards the MFC’s performance is supported by linear sweep voltammetry measurement and scanning electron microscopy observations. The ability of the MFC to sustain its discharge for a prolonged duration despite the fungal microbes not being attached to the air electrode is attributed to the formation of a network of filamentous hyphae under the submerged culture. Further, gradual lignin decomposition by fungal inocula ensures a continuous supply of laccase enzyme and radical oxidants to the MFC. These factors promote a self-sustaining MFC devoid of any control features.

https://www.mdpi.com/1996-1073/14/8/2098/pdf

Self-Sustaining Bioelectrochemical Cell from Fungal Degradation of Lignin-Rich Agrowaste

Tafel polarisation method is widely used in corrosion studies but relies heavily on the accurate extrapolation of the linear regions To eliminate the ambiguity in the linear extrapolation, the present study develops a quantitative method based on piecewise linear regression analysis In this method, the entire polarisation data is divided into small sub-intervals and variation in the regression coefficient and linearity coefficient values are observed Consistency in these values serves as a quantitative indicator of the linear Tafel regions The method described is then demonstrated in potentiodynamic polarisation measurement of Al/NaCl (05 M) and Zn/KOH (1 M) systems The piecewise linear regression analysis positively identified the linear regions from the polarisation branches and thus provided more accurate corrosion parameters of the systems

/pdf/determination-of-linear-tafel-region-from-piecewise-linear-21nngnaums.pdf

Determination of Linear Tafel Region from Piecewise Linear Regression Analysis

In this study, biochar was produced from sugarcane bagasse in a modified muffle
furnace without using a purging gas at different temperatures; 400˚C to 700˚C with
increments of 50˚C at 25˚C/min heating rate. Biochar yields were significantly influenced by
the devolatization of biomass during the pyrolysis and were inversely proportional to the
temperature. The holding time was also found to have a significant effect on biochar yields.
The maximum biochar yields from sugarcane bagasse, at 10, 20 and 30 minutes holding
times, were 27.11, 26.35, and 28.48%, respectively. The highest biochar yield at different
holding times was obtained at a temperature of 400°C. The physicochemical properties of
biomass and biochar were analysed. The results obtained from characterization showed that
SCBC30 showed the highest BET surface area of 348.12 m 2 /g. From the FTIR results,
SCBC10 showed fewer peaks, which indicated a smaller presence of functional groups than
SCB-BC20 and SCB-BC30 due to an incomplete transformation of raw SCB wastes to
biochar.

Noraini Mohamed Noor

Papers

Agricultural biomass-derived magnetic adsorbents: Preparation and application for heavy metals removal

Self-Sustaining Bioelectrochemical Cell from Fungal Degradation of Lignin-Rich Agrowaste

Determination of Linear Tafel Region from Piecewise Linear Regression Analysis

Self-purging pyrolysis of sugarcane bagasse biomass to highly order microporous biochar production

Removal of cadmium ions via the magnetic biochar synthesised from sugarcane bagasse: factors affecting yield and adsorption capability