Papers by Keyword: Heavy Metal Ion

Abstract: Many researchers have currently interested in using Fe₃O₄ magnetic nanoparticles (MNPs) impregnated onto agricultural wastes for removal of heavy metal ions in wastewater treatment process. In this work, the MNPs-pomelo peel powder (MNPs-PP) composites were developed and their adsorption capacities of heavy metal ions were studied as well. The MNPs-PP samples were synthesized by co-precipitation method in different ratios; 2:1, 2:2, 2:4, 2:5, and 2:6 (by weight). The results showed that the as-synthesized MNPs were mainly spherical shape with an average particle size of approximately 12.7 ± 0.6 nm. Then, the MNPs, PP and MNPs-PP in different ratios were used as adsorbents for adsorption of 25 ppm Cu²⁺ in aqueous solution. The pH and temperature of solution were kept constant at 5 and 30 °C, respectively. From the experiment, it was found that the adsorption capacities decreased in the following order: PP > MNPs-PP (2:6) > MNPs-PP (2:5) > MNPs-PP (2:4) > MNPs-PP (2:2) > MNPs-PP (2:1) > MNPs. It indicated that the adsorption capacity of as-synthesized MNPs-PP is significantly higher than that of sole MNPs. Furthermore, the adsorption capacities of MNPs-PP increased with increasing the weight ratio of PP. The MNPs-PP developed herein has demonstrated not only high adsorption efficiency but also have shown additional benefits such as ease to synthesis, cost-effectiveness, environmental-friendliness, and ease to separate from treated water by an external magnet.

Abstract: The modified sands compared with plain quartz sands possessed larger surface area and higher specific affinity towards heavy metal ions in waste water. Methods to synthesize modified sands have been briefly reviewed. Emphasis has been on the adsorption mechanisms and the characteristics of the modifying coatings which influence the absorbents’ efficiency and speciality.

Abstract: Adsorbent composites comprising of inorganic clay/sodium lignosulfonate graft-polymerized with acrylamide and maleic anhydride were synthesized by free radical solution copolymerization. The synthesized copolymers presented high adsorption capacity when the monomer ratio of acrylamide to maleic anhydride was 3:2 and montmrillonite was introduced as inorganic clay. The equilibrium adsorption of Pb²⁺ on these copolymers was well represented by Langmuir model which indicated that the Pb²⁺ adsorption was a monolayer chemical adsorption. The calculated adsorption capacity of the copolymers could reach a maximum of 176.70 mg/g for Pb²⁺ and 24.95 mg/g for Cu²⁺. In addition, these copolymers could selectively remove Pb²⁺ from Pb²⁺/Cu²⁺ binary solution and the maximum selective coefficient of Pb²⁺ to Cu²⁺ was 11.939.

Abstract: One of the factors that determine the humankind existence and development is the environment. Man as a biological system is a part of nature, however the cooperation between them is quite complex [1]. On the one hand, men need permanent protection against it’s negative impact, on the other hand, they are the source of these impacts themselves [1, 2].Thanks to their unique characteristics, natural zeolites (NZ) are widely applied for solution of different ecological problems as cheap and available sorbing agents and also as basics for catalytical materials that are used for aquatic and air medium purification [3, 4]. The most frequently applied NZ are clinoptilolites that are widespread on the territory of Russia [5, 6].

Abstract: Nanofiltration membrane was prepared by static layer-by-layer (LBL) self-assembly of poly (ethyleneimine) (PEI) and poly (sodium 4-styrenesulfonate) (PSS) on the modified poly-arcylonitrile ultra-filtration membrane. Study on self-assembly of polyelectrolyte membranes with changing surface charges and wettability, rejection properties of nanofiltration membrane in different conditions and pH with respect to heavy metal ions, namely Ni²⁺ and Cd²⁺were investigated. The results show that the PEI/PSS membrane composed of 4 bilayers at operating pressure 0.4MPa, rejection of PAN-PEI/PSS nanofiltration membrane towards these 2 kind of heavy metal ions reached no less than 90%.

Abstract: Experiment used the microwave and the adjustment of pH to modify corncob to adsorb heavy metal ions (Zn²⁺, Pb²⁺) from Water. In order to find out the best adsorption condition on the liquor which concentrations of Zn²⁺ and Pb²⁺ were 30 mg/L respective, the experiment used method of control variables and the modified corncob adsorption rate of Zn²⁺ was the reference index. The results indicated that when corncob diameter, dosage, absorbing time, shaking speed and the pH value of liquor zinc chloride were 1.5mm, 20mg/L, 30min, 180rpm and 6, respectively, the adsorption rate of Zn²⁺ and Pb²⁺ reached the highest by 76.67% and 98.54%. The results showed that modified corncob adsorption rate of Zn²⁺ and Pb²⁺ were more than 80% and 98% at low concentrations. In conclusion, modified corncob had a good adsorption property of heavy metal ions in water.

Abstract: Using the phosphogypsum as adsorbent prepared from microwave modified for the removal of lead ions from aqueous solution has been investigated under optimized conditions in this study. Influences of parameters like adsorbent dose 0.5-1.5g/100mL, initial concentration of ions 20–60 mg/L , pH 5.0–7.0 and temperature 20–30°C on Pb ions adsorption were also examined, using Box-Behnken design matrix. Very high regression coefficient between the variables and the response indicates excellent evaluation of experimental data by second order polynomial regression model. The response surface method indicated that adsorbent dose 1.0g/100mL, initial concentration of ions 40mg/L , pH 7.0 and temperature 20°C were optimal for adsorption of Pb ions .

Abstract: The novel magnetic nanocomposites have been prepared by simultaneous forming of Fe₃O₄ nanospheres and graphene sheets in an anchoring mode and polymerizing of pyrrole on the Fe₃O₄ surface. TEM, XRD and XPS were used to characterize the as-prepared products. Nanocomposites exhibit excellent adsorption capability of 348.4 mg g^-1 for heavy metal Cr (VI) ions, and moreover, are stable, separable easily under external magnetic field and recyclable, retaining about 83.1% of the removal efficiency after four adsorption-desorption cycles. The adsorption isotherm has been studied and shows a good consistency with the Langmuir mode. The nanocomposites could be a good candidate for efficient removal of Cr (VI) from the wastewater.

Abstract: This paper presents a new decoration view functionalization of mesoporous silica to extend their applications to heavy metal ion removal. The study showed that Hacac can be incorporated into the structure through in-situ strategy, and the calcined Hacac-silica possesses advantages of high specific surface area of about 1496 m²/g and pore size of 4nm, ordered spheric morphology of about 300nm in diameter. Auxiliary by ultrasonic technology, the heavy metal ions remove rates are more than 95% for Pb²⁺, Cu²⁺ and Cr³⁺. More choice of chelating agents can be used for further functionalization of silica based mesoporous material.

Abstract: Separation of trace heavy metal ions with BaS from solutions of five kinds of systems was studied. One was prepared with the solution (called as original solution here) leached from pyrolusite with pyrite and H₂SO₄, and the other four kinds of systems were prepared in the laboratory according to the composition of the original solution. They are respectively: a ternary system of NiSO₄CoSO₄ZnSO₄; two quaternary systems of (NH₄)₂SO₄NiSO₄CoSO₄ZnSO₄ and MnSO₄NiSO₄CoSO₄ZnSO₄; a quintuple system of MnSO₄(NH₄)₂SO₄NiSO₄CoSO₄ZnSO₄. The experiments have researched the effect of reaction time and dosage of BaS on the separation of heavy metal ions. According to the results, it took the five systems 10minutes to reach the equilibrium state and re-dissolution was found in the results. As the increasing of BaS dosage, the residual heavy metal ions would reduce, but the results of five systems were different when the same BaS was used.