In this study, adsorption of the heavy metal ions (Pb(II), Cu(II) and Cd(II)) from water by peanut shells (PS), sawdust (S) and commercial activated carbon (AC) were comparatively studied. Thus, the relationship between different adsorption parameters and different heavy metal ion removal rates was investigated. The adsorption capacity of the three adsorbents for heavy metal ions increased with an increase in temperature, pH value, contact time, adsorbent dosage, and heavy metal ion concentration, however, it decreased with an increase of adsorbent particle size. All the adsorption processes are better described by Langmuir isotherm or Freundlich isotherm. Thus, the results show good agreement with pseudo-second-order kinetics and the adsorption processes are spontaneous heat absorption processes. Herein, all adsorbents have higher affinity for Pb(II) ions, and hence possess higher removal rates. In addition, heavy metal ions were desorbed significantly at acidic conditions in the desorption experiments. The results demonstrate that PS can be used as a green adsorbent instead of AC for the adsorption of heavy metal ions from the water.

In this work, the experimental study of unconfined compressive strength tests, direct tensile strength tests and three point bending tests were carried out to evaluate the effect of PVA fiber reinforcement on the mechanical behaviour of cemented silty soil. In general, the addition of polyvinyl alcohol (PVA) fiber lead to an increase in compressive strength, and it was observed more significant improvement in tensile strength and flexural strength, moreover, the inclusion of fibers effectively altered the brittle failure pattern of unreinforced cemented soil and improve the toughness and ductility. In addition, the microstructural of interaction between fibers and cemented soil was investigated. The proposal of regression model was utilized for predicting compressive strength, tensile strength and flexural strength.