Elimination of water hardness using citric acid modified almond shell

In this study, the potential of the water hardness to be removed and the regeneration ability of the biomass used are investigated using almond shell, a lignocellulosic material. Standard hardness removal experiments, continuous system hardness removal experiments, characterization tests and chemical analyzes were performed by selecting the most appropriate size fractions of the samples modified with crude, saponified and citric acid. It is obvious that the almond shell is a physico-chemically valuable material and that the modification process significantly improved its physicochemical properties. This property can be regarded as an advantage in terms of its use as a column filler material. It was also observed that the ability of the almond shell to change the cation, after significant citric acid esterification, increased significantly. With citric acid almond shell material, total hardness removal efficiency of 85% was achieved in cut systems. In the continuous systems, the total hardness per unit bed weight was 33,25 mg CaCO3/g, while the yield in the outlet water was 80%, the total hardness per unit bed weight was 23,1 Mg CaCO3/g. As a result of applying ten consecutive stiffness-regeneration cycles, it was observed that over 95% of the regeneration steps achieved a desorption efficiency of over 95%. As a conclusion, it is considered that the almond shell can be used as a good ion exchanger in citric acid, by modifying it with simple processes, in the removal of hardening ions from the water, and in long service times by successive sorption-regeneration processes.