A magnetic separation study was conducted employing magnetized zeolite and a high gradient magnetic separation system (HGMS) for removal of both cationic and anionic heavy metals. Magnetized zeolite Y was prepared with variable iron contents ranged from 1.2-22.8% based on surface concentration. The magnetized zeolite showed decreased adsorption capacity for cations while the adsorption capacity of the adsorbent for anion increased and the adsorption capacity was proportional to the iron contents. The captured rate of dispersed adsorbents after use for removal of contaminants is a very important factor in water treatment processes. The magnetic separation system recovered more than 98% of magnetized zeolite at 3 T of magnetic field. Current result indicates the combination of magnetized zeolite and HGMS separation could be an efficient alternative for simultaneous removal of cationic and anionic heavy metal from water phase.

Fish that inhabited in the watersheds of Andong, Imha and Yeongju Dam in the upper Nakdong River were analyzed heavy metals by separated into muscle, gill, stomach and liver part.Thirteen fish species such as dark chub, skygager, coreoperca herzi, Korean piscivorous chub, cornet fish, Japan crucian carp, catfish, bass, crucian carp, mandarin fish, carp, long-nosed barbel, Korean sharpbelly were analyzed using ICP/MS.The results of the analysis based on the overall average concentration showed that the muscle part is lower than other parts in all heavy metal items except mercury.The gill part showed high concentrations of chromium, manganese, nickel, and lead, the stomach part has high zinc, and the liver part showed high concentrations of iron, copper, arsenic, and cadmium.

A selective removal of certain ions from aqueous phase containing common ions is very useful in engineering aspect because the process allows removal of toxic substances only or recovery of valuable ion species. The ion imprinting technology has shown great potential in the synthesis of materials that are capable of adsorbing a metal ion selectively. In current study, a Pb (II) imprinted magnetic polymer was synthesized using surface imprinting technique employing Pb (II) as template, polyethyleneimene functionalized magnetic Fe3O4 as functional monomer and epoxy chloropropane as cross-linker. The magnetic adsorbent was successfully imprinted, and the ion imprinted sorbent was used for selectivity test for Pb (II). Through the imprinting process, the shape of sorbent has changed, and the magnetic properties have decreased. This is an adverse effect of the polymer formed on the surface of the sorbent by the imprinting. The synthesized magnetic adsorbent was recovered from aqueous phase by a high gradient magnetic separation (HGMS) system with a superconducting magnet. The magnet is a cryo-cooled Nb-Ti superconduction magnet. Magnetic filter (SUS 403, 10 mesh) was used for the magnetic separation. The synthetic polymer with small particle size and weak magnetic properties successfully recovered the by the HGMS system and the recovery efficiency was improved with increased magnetic field of the superconducting magnet. By the magnetic separation, the adsorbent could be recovered and reused after the selective adsorption process for a heavy metal removal. The prepared Pb (II) imprinted magnetic adsorbent was also characterized by transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). Batch selectivity studies were performed to evaluate the influence of competing ions such as Cd (II), Ni (II), and Cu (II). The selectivity coefficients of Pb (II)/Cd (II), Pb (II)/Ni (II) and Pb (II)/Cu (II) were calculated as 1.89, 3.57 and 11.23 respectively.

There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

Radioactive cesium was released from nuclear accidents such as Fukushima and Chernobyl's nuclear power plant accident. The released cesium contaminated the water and soil environment around the accident area. Common environmental technologies for water and soil could not be used for the cesium-contaminated environment due to several reasons. The radioactive cesium exists as in a trace amount and with other common cations such as calcium and sodium. The coexisting cations interfere the removal of cesium and increase the final waste. Magnetic separation combined with adsorption technology can be applicable to the removal of radioactive cesium from water environments. In current study, a selective adsorbent for cesium, i.e., silicotitanate, was synthesized and tested for cesium selectivity. The cesium-selective adsorbent was magnetized and separated from water using a superconducting magnet. The decrease of sorption capacity was evaluated after magnetization. The cesium selectivity was sustained after the magnetization. The removal efficiency of magnetized silicotitanate was highly dependent on the magnetic field and magnetizing method. Complete removal of the magnetized adsorbent was achieved by a superconducting magnet, indicating that a superconducting magnet system with magnetized silicotitanate can be an alternative for water treatment from nuclear accident sites.