PMC:4764609 / 15852-16607 JSONTXT

{"project":"2_test","denotations":[{"id":"28330153-23437666-715","span":{"begin":340,"end":344},"obj":"23437666"}],"text":"Effect of pH on adsorption\nThe pH of the aqueous metal solution affects sorption through the adsorbent surface charge, the degree of ionization and speciation of the adsorbate as well. Maximum  % removal of copper was 94.47 % at pH 6 (Fig. 1b) and this is in agreement with the earlier research reports (Rafatullah et al. 2010; Chen et al. 2012). At pH \u003c 5, the number of sites available for metal adsorption will be low as most of the functional groups are protonated and H3O+ ions compete with the metal for the adsorption sites on the adsorbent. At pH 6, the increase in adsorption could be attributed to the weak inhibitory effect of H3O+ ions. At pH above 6, the adsorption rates were unpredictable due to accumulation of metal ions on the adsorbent."}