Biochar efficiency in copper removal from Haplic soils

A Tomczyk,P Boguta,Z Sokołowska

doi:10.1007/s13762-019-02227-4

Abstract

The main aim of the study was to examine the biochar efficiency in copper (Cu) ion removal from Haplic (Luvisol, Podzol) soils. In other words, the most effective biochar dose and the most favorable environment pH value were proposed. The copper removal was carried out based on the adsorption process. The results of kinetics measurements were modeled using Richie equation, whereas the adsorption isotherms using Langmuir–Freundlich and Dubinin–Radushkevich equations. The copper removal is a strongly pH-dependent process which is associated with variability of chemical Cu forms and various reactivities of organic molecules. The Cu adsorption amount was higher on silty Haplic Luvisol than on sandy Haplic Podzol mainly due to higher content of organic carbon, functional groups, clay and silt fractions as well as larger surface area. Moreover, the biochar addition increased linearly the soil surface charge and contributed to higher copper adsorption in the whole range of investigated ion concentrations. The higher the biochar dose added, the more Cu ions were adsorbed.

Highlights

Copper (Cu) is a heavy metal found in soils mostly in the form of sulfides, sulfates and carbonates
The important topic of sorption of heavy metals, such as Cu by biochar added to soils, was discussed
The comprehensive approach for the research problem taking into account different soils and doses of biochar as well as wide range of pHs allowed to receive valuable information on adsorption properties of biochar in soil environment

Summary

Introduction

Copper (Cu) is a heavy metal found in soils mostly in the form of sulfides, sulfates and carbonates. Depending on environmental conditions like pH, ionic strength, temperature, concentration and molecular weight of organic particles contained in soil, Cu may be in soluble or insoluble form (Aydin and Bulut 2008; Pendias and Kabata-Pendias 1999). Cu can form strongly bonded complexes with soil organic matter and clay minerals. Under less-favored conditions, Cu may be released in uncontrolled way and pollute soil environment due to its toxic effect (Aman et al 2008)

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