Digital Commons Network^™

Comparative Sorption Of Pb And Cd By Biochars And Its Implication For Metal Immobilization In Soils, Jin Hee Park, Girish Choppala, Seul Lee, Nanthi Bolan, Jae Chung, Mansour Edraki

Dr Girish Choppala

Biochar has great potential as a soil amendment to immobilize heavy metals, thereby reducing their bioavailability. In this study, biochars derived from chicken manure and green waste were compared with commercial activated carbon (AC) and laboratory produced black carbon (BC) for the sorption of Pb and Cd. Sorption kinetics and equilibrium sorption isotherms for Pb and Cd were obtained for the char materials and the data were fitted to kinetic and sorption isotherm models.. Chicken manure-derived biochar (CM) showed the highest sorption capacity for both Pb and Cd, and the Pb sorption by biochars was higher than the Cd sorption …

Phytocapping: An Alternative Technology For The Sustainable Management Of Landfill Sites, Dane Lamb, Kartik Venkatraman, Nanthi Bolan, Nanjappa Ashwath, Girish Choppala, Ravi Naidu

Dr Girish Choppala

Landfill remains the predominant means of waste disposal throughout the globe. Numerous landfills exist in developed and underdeveloped countries, engineered with contrasting degrees of effectiveness. Modern landfill closure in developed countries involves the conventional capping of waste with materials such as compacted clay or geosynthetic clay liners, typically overlain with other soil materials. Conventional capping technologies are now accepted to be increasingly ineffective in reducing percolation into waste. Cost-effective alternative systems are of increasing interest, including the use of plants to control and limit water entry into waste, otherwise known as “Phytocapping”. Phytocapping reduces percolation through three main mechanisms: (a) …

Chemodynamics Of Chromium Reduction In Soils: Implications To Bioavailability, Girish Choppala, Nanthi Bolan, Belaji Seshadri

Dr Girish Choppala

Chromium toxicity in soils can be mitigated by reduction of Cr(VI) to Cr(III) which is influenced by the presence of free Cr(VI) species in soil solution, and the supply of protons and electrons. In this study, the effects of Cr(VI) adsorption (i.e. availability of free Cr(VI) species in soil solution), soil pH (i.e. supply of protons) and three electron donor carbon sources [black carbon (BC), chicken manure biochar (CMB) and cow manure (CM)] on the reduction of Cr(VI) to Cr(III) in soils were investigated. The results indicated that the rate of Cr(VI) reduction decreased with an increase in Cr(VI) adsorption …

Concomitant Reduction And Immobilization Of Chromium In Relation To Its Bioavailability In Soils, Girish Choppala, Nanthi Bolan, Anitha Kunhikrishnan, William Skinner, Balaji Seshadri

Dr Girish Choppala

In this study, two carbon materials [chicken manure biochar (CMB) and black carbon (BC)] were investigated for their effects on the reduction of hexavalent chromium [Cr(VI)] in two spiked [600 mg Cr(VI) kg−1] and one tannery waste contaminated [454 mg Cr(VI) kg−1] soils. In spiked soils, both the rate and the maximum extent of reduction of Cr(VI) to trivalent Cr [Cr(III)] were higher in the sandy loam than clay soil, which is attributed to the difference in the extent of Cr(VI) adsorption between the soils. The highest rate of Cr(VI) reduction was observed in BC-amended sandy loam soil, where it …

Biochar Reduces The Bioavailability And Phytotoxicity Of Heavy Metals, Jin Hee Park, Girish Choppala, Nanthi Bolan, Jae Chung, Thammared Chuasavathi

Dr Girish Choppala

Background and aims

Biochar has attracted research interest due to its ability to increase the soil carbon pool and improve crop productivity. The objective of this study was to evaluate the metal immobilizing impact of chicken manure- and green waste-derived biochars, and their effectiveness in promoting plant growth.

Methods

The immobilization and phytoavailability of Cd, Cu and Pb was examined using naturally contaminated shooting range and spiked soils. Biochar samples prepared from chicken manure and green waste were used as soil amendments.

Results

Application of biochar significantly reduced NH₄NO₃ extractable Cd, Cu and Pb concentrations of soils, …

Stabilization Of Carbon In Composts And Biochars In Relation To Carbon Sequestration And Soil Fertility, Nanthi Bolan, Anitha Kunhikrishnan, Girish Choppala, R Thangarajan, J Chung

Dr Girish Choppala

There have been increasing interests in the conversion of organic residues into biochars in order to reduce the rate of decomposition, thereby enhancing carbon (C) sequestration in soils. However energy is required to initiate the pyrolysis process during biochar production which can also lead to the release of greenhouse gasses. Alternative methods can be used to stabilize C in composts and other organic residues without impacting their quality. The objectives of this study include: (i) to compare the rate of decomposition among various organic amendments and (ii) to examine the effect of clay materials on the stabilization of C in …