Potential of Saudi natural clay as an effective adsorbent in heavy metals removal from wastewater

Abstract

Potential of Saudi natural clay as an effective adsorbent for removal of heavy metals from wastewater This study aims to examine the potential of natural clay mineral from the southern part of Saudi Arabia as an effective adsorbent material for the removal of heavy metal ions of cadmium (Cd) and nickel (Ni) from aqueous solutions. The SEM analysis showed that clay particles had mixed shapes such as elongated rod-like and rectangular shape having rough corners with larger particles of 2-8 µm in size and smaller particles in the sub-micron size range. XRD data revealed that clay particles had a good crystalline structure and composed of a mixture of various minerals including feldspar, Illite, quartz, calcite, and gypsum. The BET surface area was found to be 35±1 m 2 /g and the average pore size and pore volume of 6.5±0.5 nm and 5.7e-02 cc/g respectively. The XRF analysis of clay showed main compounds of SiO2 (47.33%), Al2O3 (18.14%), Fe2O3 (15.89%) with many others e.g. CaO, MgO, TiO2, and K2O in minor quantities. It was found that 1.2 g of clay removed up to 99.5% of Ni and 97.5% of Cd from 40 ppm aqueous solutions. The metal removal efficiencies were increased from around 95% up to 99% by increasing the pH of aqueous solutions from 4 to 11. The adsorption of Ni and Cd ions on Saudi clay was relatively fast, and up to 97% of ions were removed from solution within 45 min. The SEM-EDX analysis for recycled clays further confirmed that the metal ions were removed from water through adsorption onto the clay. The experimental data fitted well with Langmuir and Freundlich isotherms. The maximum adsorption capacity of clay for Cd and Ni from isotherms was found to be 3.3 and 2.7 mg/g respectively. The findings of this study confirm the potential role of Saudi natural clay in wastewater treatment processes as a cheap, environmentfriendly and safe natural adsorbent material.

Efficient Removal of Ni(II) from Aqueous Solution by Date Seeds Powder Biosorbent: Adsorption Kinetics, Isotherm and Thermodynamics

“…Figure 7 proves that the system obeys the pseudo-second-order kinetics model. This is in good agreement with previous studies [12,13,15].…”

“…Mesopores are detected over the entire sample surface forming a highly uniform and interpenetrating permeable media. Moreover, results also confirm that DSP has a large surface area compared to some other adsorbents used to adsorb Ni(II) ions [13].…”

Adsorption of methylene blue onto natural Saudi Red Clay: isotherms, kinetics and thermodynamic studies

“…X-ray florescence (XRF) analysis were performed on the ZSX Primus II (Rigaku, USA) to determine the metal oxide contents of the clay sample as presented in table 1. The samples for XRF analysis were prepared according the procedure mentioned in [31] and finally analyzed using XRF spectrometer. Surface area measurements (S BET ) together with other relevant data were carried out from the nitrogen adsorption-desorption plots using Brunauer-Emmett-Teller (BET) method.…”

“…The effect of contact time was also studied with contact time ranging from 5 min up to 1 h. In order to study the batch kinetics of the adsorption process, the remaining concentration of MB in the solution was studied at pre-determined intervals of time. According to [31] the percentage dye removal can be calculated as follows:…”

Waste Engine Oil Remediation Using Low Cost Natural Clay Absorbent Material

“…Clays are known to be a permeable media [9], that usually possess high surface area and active sites making the clay as potential adsorbent. Different types of clays have proven to have the ability to act as bleaching agent, particularly bentonite [10,11]. Natural unmodified clays tend to attract oil molecules to its solid surface by weak Van der Waal forces postulating that the adsorption mechanism is physisorption in nature.…”