Biochar from Pyrolysis of Deinking Paper Sludge and Its Use in the Remediation of Zn‐polluted Soils

Abstract

An increasing proportion of recycled fibres are used in paper industries. Removing the ink, clay, coatings and contaminants from paper waste in order to produce recycled fibres creates large amounts of deinking paper sludges. The preparation of biochar from pyrolysis of this waste and its use in soil remediation contaminated with heavy metals could be an interesting valorization alternative. Our aim was to study the influence of biochar from deinking paper sludge (HP) pyrolysis in the treatment of Zn‐polluted soils. Three different soils contaminated with 2000 mg Zn kg−1 were amended at a rate of 10% with deinking paper sludge and deinking paper sludge biochar prepared at three different temperatures (300, 400 and 500 °C). Soils were incubated under laboratory conditions, and soluble Zn was measured. The addition of biochar reduced the amount of mobile Zn. Finally, Zn solubility decrease was more pronounced for biochars prepared at a higher temperature. Copyright © 2016 John Wiley & Sons, Ltd.

Creation of Technosols to Decrease Metal Availability in Pyritic Tailings with Addition of Biochar and Marble Waste

“…The higher content of carbonates in MSW‐derived biochar promoted increases in soil pH up to 5·5, and the addition of MaW did not contribute to further decrease metal mobility. Previous research has also reported that pH is the main driven factor controlling metal mobility with addition of amendments (Ahmad et al ., ; Rajapaksha et al , ; Paz‐Ferreiro et al ., ). Thus, the addition of warble waste as a source of CaCO 3 is confirmed as a sustainable material for the creation of Technosols from pyritic tailings to decrease metal toxicity, also observed in previous studies (Pardo et al , ; Zornoza et al , ).…”

“…Addition of biochar was also directly involved in the immobilization of Cd and Zn by retention in its oxidizable fraction (organic compounds) (Figure ), a trend reported by previous authors (Adriano et al ., ; Harvey et al ., ; Mohamed et al ., ). This could be related to adsorption processes, because biochars, and mostly those prepared at high temperature, have a larger surface area, which can complex metals (Paz‐Ferreiro et al , ). Mohamed et al .…”

“…A variety of stabilizing materials have been used such as cement, lime, mussell shell, marble waste (MaW), glacial till, iron oxide, nanomaterials, peat, manure, compost or biochar (Pardo et al , ; Zornoza et al , ; Moon et al ., ; Ahmad et al, ; Rajapaksha et al. , ; Paz‐Ferreiro et al ., ; Smart et al ., ). The primary mechanisms of metal immobilization by stabilizing agents are cation exchange, adsorption, complexation and precipitation (Ahmad et al ., ).…”

“…Biochar is a porous, carbonaceous product obtained from the pyrolysis of a great variety of organic materials, with large surface area, high cation‐exchange capacity and high pH (Paz‐Ferreiro et al , ). Thus, biochar has resulted highly effective to decrease soil metal mobility through direct increases in soil pH and by cation exchange and direct adsorption (Moon et al , ; Ahmad et al ., ; Paz‐Ferreiro et al , , ).…”

Impact of biochar properties on soil conditions and agricultural sustainability: A review

“…Although biochar application has shown some variable results, depending on soil type, biochar feedstock, biochar pyrolysis temperature, and other environmental factors; there are a number of potential positive aspects associated with the use of biochar as a soil amendment, including increased soil nutrient availability and uptake by plants (Sigua, Novak, Watts, Johnson, & Spokas, ; Zornoza, Moreno‐Barriga, Acosta, Muñoz, & Faz, ); enhanced organic and inorganic fertilizers use efficiency (Schulz & Glaser, ); increased soil mineral N (NH 4 and NO 3 ) retention (Clough, Condron, Kammann, & Müller, ); reduced nutrient losses and fertilizer demand (Ding et al, ); improved soil physical properties (soil water holding capacity, soil aeration, bulk density, porosity, aggregate stability, infiltration rate, and hydraulic conductivity; Atkinson, Fitzgerald, & Hipps, ; Mukherjee & Lal, ); increased base saturation and liming effect on acidic soils (Wang et al, ); stabilization of heavy metals and reduced bioavailability to plants growing in contaminated soils (Ahmad et al, ; Paz‐Ferreiro, Plasencia, Gascó, & Méndez, ); stimulation of microbial populations and functioning (Zhu, Chen, Zhu, & Xing, ); increased crop performance and productivity (Jeffery, Verheijen, van der Velde, & Bastos, ); enhanced symbiotic N fixation in legumes (Mia et al, ); reduced salinity, drought, and heat stresses impact on plant growth and soil properties (Ali et al, ; Drake, Cavagnaro, Cunningham, Jackson, & Patti, ; Fahad et al, ). In conjunction with chemical fertilizers, biochar improves the nutrient use efficiency of plants by enhancing soil nutrient retention for a longer period of time, and via the slow release of nutrients according to plant requirements (DeLuca, MacKenzie, & Gundale, ).…”