Investigation of arsenic removal from water using activated carbon produced from agricultural wastes

In this study, activated carbon derived from agricultural waste was used as tertiary treatment. Activated carbon powder was used in laboratory-scale experiments and was performed for arsenic removal from synthetics samples.1 physically activated carbon was obtained and then chemically activated by acidification. Characterization tests (i.e. XRD, FT-IR, BET and SEM tests) were carried out on both types of adsorbent.2 Arsenic removal was carried out in batch experiments. Effect of laboratory parameters (i.e. contact time, pH, adsorbent dose and initial concentration) on removal process was studied. Chemical activation, improved performance and characteristics of adsorbent.3 The improvements was observed in chemical structure (reducing the number of phases and improve the chemical bonds of the material), increasing specific surface (from 1067.4 to 1437 m2/g), uniformity of pore size distribution, reduction of average pore size diameter (from 2.08 to 3.28 nm) and modified adsorbent pore network structure as shown in Table 1. The results showed that in optimum conditions, removal efficiency was 100% and maximum capacity of adsorbent was 120 μg/g. Optimum conditions was pH=5 and equilibrium contact time of 10 minutes. Kinetic and equilibrium studies showed that adsorption process, followed of Langmuir isotherm and second-degree kinetic models.

Keywords:

Adsorption , Arsenic , Walnut shell , Chemical Activation