Investigation on the Effect of the Tension Degree of Tracks on the Adsorption Performance of Tracked Wall Climbing Robot

In this paper,a new tracked wall climbing robot with permanent magnetic units is designed,and the tension degree of robot’s tracks is found to have a significant impact on the robot’s adsorption performance.This tracked wall climbing robot is a remotely controlled robot.All the control devices can be installed on the robot body.All the permanent magnetic units are arranged on the light track.In order to illustrate the relationship between the tension degree and the adsorption performance,when absorbed on the vertical surface and 180⁃degree inverted surface,the static force analysis of the robot is presented.Finally,experiments were demonstrated to prove that higher tension degree of tracks can make adsorption performance better.

Adsorption and Desorption of Gold on the Magnetic Activated Carbon

Adsorption and desorption of gold on the magnetic activated carbon (MAC) were investigated The adsorption rate of gold is higher than that of conventional coconut carbon in cyanide leach solution The loading gold can be easily desorbed as coconut carbon. Crushed fine magnetic carbon can be selected by a magnetic separator, It is suggested that the MAC can be used in carbon-in-pulp (CIP)process for increasing the recovery rate of gold

Structural,electronic,and magnetic properties of transition-metal atom adsorbed two-dimensional GaAs nanosheet

By using first-principles calculations within the framework of density functional theory,the electronic and magnetic properties of 3d transitional metal（TM） atoms（from Sc to Zn） adsorbed monolayer Ga As nanosheets（Ga As NSs） are systematically investigated.Upon TM atom adsorption,Ga As NS,which is a nonmagnetic semiconductor,can be tuned into a magnetic semiconductor（Sc,V,and Fe adsorption）,a half-metal（Mn adsorption）,or a metal（Co and Cu adsorption）.Our calculations show that the strong p–d hybridization between the 3d orbit of TM atoms and the 4p orbit of neighboring As atoms is responsible for the formation of chemical bonds and the origin of magnetism in the Ga As NSs with Sc,V,and Fe adsorption.However,the Mn 3d orbit with more unpaired electrons hybridizes not only with the As 4p orbit but also with the Ga 4p orbit,resulting in a stronger exchange interaction.Our results may be useful for electronic and magnetic applications of Ga As NS-based materials.

Modification of a magnetic carbon composite for ciprofloxacin adsorption

A magnetic carbon composite, Fe3O4/C composite, was fabricated by one-step hydrothermal synthesis, modified by heat treatment under an inert atmosphere（N2）, and then used as an adsorbent for ciprofloxacin（CIP） removal. Conditions for the modification were optimized according to the rate of CIP removal. The adsorbent was characterized by Fourier transform infrared spectroscopy, X-ray diffraction measurements, vibrating-sample magnetometry,scanning electron microscopy, transmission electron microscopy, and N2adsorption/desorption isotherm measurements. The results indicate that the modified adsorbent has substantial magnetism and has a large specific area, which favor CIP adsorption. The effects of solution p H, adsorbent dose, contact time, initial CIP concentration, ion strength, humic acid and solution temperature on CIP removal were also studied. Our results show that all of the above factors influence CIP removal. The Langmuir adsorption isotherm fits the adsorption process well, with the pseudo second-order model describing the adsorption kinetics accurately. The thermodynamic parameters indicate that adsorption is mainly physical adsorption. Recycling experiments revealed that the behavior of adsorbent is maintained after recycling for five times. Overall, the modified magnetic carbon composite is an efficient adsorbent for wastewater treatment.

Highly efficient removal of Cr(Ⅵ)from wastewater via adsorption with novel magnetic Fe_3O_4@C@MgAl-layered double-hydroxide

Novel magnetic Fe3O4@C@MgAl-layerecl double-hydroxide（LDH） nanoparticles have been successfully prepared by the chemical self-assembly methods.The properties of surface functional groups,crystal structure,magnetism and surface morphology of magnetic nanoparticles were characterized by Fourier transform infrared spectroscopy（FT-IR）,X-ray diffraction（XRD）,thermal gravity-differential thermal gravity（TG-DTG）,scanning electron microscopy（SEM）,and transmission electron microscopy（TEM）.The adsorption studies of the novel adsorbent in removing heavy metals Cr（Ⅵ） from waste water showed that the maximum absorption amount of Cr（Ⅵ） was 152.0 mg/g at 40℃ and pH 6.0.The excellent adsorption capacity of the Fe3O4@C@MgAl-LDH nano-absorbents plus their easy separation,environmentally friendly composition and reusability makes them more suitable adsorbents for the removal of metal ions from waste water.

Synthesis,characterization and application of Lagerstroemia speciosa embedded magnetic nanoparticle for Cr(Ⅵ)adsorption from aqueous solution

Lagerstroemia speciosa bark（LB） embedded magnetic nanoparticles were prepared by co-precipitation of Fe2＋ and Fe3＋ salt solution with ammonia and LB for Cr（Ⅵ） removal from aqueous solution.The native LB,magnetic nanoparticle（MNP）,L.spedosa embedded magnetic nanoparticle（MNPLB） and Cr（Ⅵ） adsorbed MNPLB particles were characterized by SEM-EDX,TEM,BET-surface area,FT-IR,XRD and TGA methods.TEM analysis confirmed nearly spherical shape of MNP with an average diameter of 8.76 nm and the surface modification did not result in the phase change of MNP as established by XRD analysis,while led to the formation of secondary particles of MNPLB with diameter of 18.54 nm.Characterization results revealed covalent binding between the hydroxyl group of MNP and carboxyl group of LB particles and further confirmed its physico-chemical nature favorable for Cr（Ⅵ） adsorption.The Cr（Ⅵ） adsorption on to MNPLB particle as an adsorbent was tested under different contact time,initial Cr（Ⅵ） concentration,adsorbent dose,initial pH,temperature and agitation speed.The results of the equilibrium and kinetics of adsorption were well described by Langmuir isotherm and pseudo-second-order model,respectively.The thermodynamic parameters suggest spontaneous and endothermic nature of Cr（Ⅵ）adsorption onto MNPLB.The maximum adsorption capacity for MNPLB was calculated to be 434.78 mg/g and these particles even after Cr（Ⅵ） adsorption were collected effortlessly from the aqueous solution by a magnet.The desorption of Cr（Ⅵ）-adsorbed MNPLB was found to be more than 93.72%with spent MNPLB depicting eleven successive adsorption-desorption cycles.

Chemically modified magnetic chitosan microspheres for Cr（VI） removal from acidic aqueous solution

A bioadsorbent composed of magnetic silica nanoparticles encapsulated by chitosan microspheres was prepared by the emulsion cross-linking method, and it was then modified with quaternary ammonium groups by reaction with ethylenediamine and glycidyl trimethylammonium chloride. Characterization of the bioadsorbent indicated that it was highly acid resistant and magnetically responsive. The bioadsor- bent was then used to remove Cr（VI） from acidic aqueous solution. The results of batch experiments indicated that the optimal pH value was 2.5, and the adsorbent exhibited low pH dependence. The maximum adsorption capacity was 233.1mg/g at pH 2.5 and 25 ℃, and the equilibrium time was deter- mined to be 40-120 min depending on the initial Cr（VI） concentration. The adsorbent could be effectively regenerated using a mixture of 0.3 mol/L NaOH and 0.3 mol/L NaCI with a desorption efficiency of 95.6%, indicating high reusability. In conclusion, the bioadsorbent shows potential for Cr（VI） removal from acidic

Cd(Ⅱ)removal from amino acids-bearing wastewater:Critical evaluation and comparison of using magnetic carbon nanotubes vs.magnetite

In the present work,two magnetic adsorbents(magnetic carbon nanotunes“MCNT”and magnetite“Mag”)were tested for cadmium“Cd(Ⅱ)”removal from water in the presence of various amino acids“AA”(aspartic acid,glutamic acid“Glu”,glycine and cysteine).MCNT was prepared by initially oxidizing carbon nanotubes(CNT)by three different methods:nitric acid method,ammonium persulphate method,Hummer's method.Magnetite was then deposited on the oxidized CNT to produce the corresponding magnetic carbon nanotube adsorbents:NA-MCNT,APS-MCNT,HUM-MCNT,respectively.Adsorption of Cd(Ⅱ)on various MCNT was investigated in the presence/absence of AA where various factors were studied:pH,oxidation method of CNT,type of AA,magnetite-to-CNT ratio.It was found that the presence of AA significantly reduced the adsorption capacity of MCNT towards Cd(Ⅱ)at all pHs(reduction occurred from 49.8 mg g^(-1)to 12.5 mg g^(-1)).Contrary adsorption capacity of Cd(Ⅱ)on bare magnetite“Mag”was noticeably enhanced in the presence of AA(for Glu,enhancement occurred from 6.9 to 22.3 mg g^(-1)).Due to cheapness of Mag relative to CNT,it was recommended to use Mag rather than MCNT for Cd(Ⅱ)removal from AA-bearing water.So that the optimum uptake method was proposed using Mag at pH 8 in the presence of Glu at concentration ratio(1:3 Cd(Ⅱ):Glu).Mag was selective towards Cd(Ⅱ)even in the presence of co-existing ions.The use of Mag for five cycles decreased adsorption efficiency to 80%which indicated that adsorption system was cost effective.Real water samples gave higher adsorption of Cd(Ⅱ)in the presence of Glu than in distilled water.As a conclusion,it was recommended to use Mag rather than MCNT for Cd(Ⅱ)removal in the presence of AA.

Efficient removal of phosphate from aqueous solution using novel magnetic nanocomposites with Fe_3O_4@SiO_2 core and mesoporous CeO_2 shell

Fe_3O_4@SiO_2 magnetic nanoparticles functionalized with mesoporous cerium oxide（Fe_3O_4@SiO_2@mCeO_2） was fabricated as a novel adsorbent to remove phosphate from water. The prepared adsorbent was characterized by X-ray diffractometry（XRD）, transmission electron microscopy（TEM）, nitrogen adsorption-desorption and vibrating sample magnetometry（VSM）, and its phosphate removal performance was investigated through the batch adsorption studies. Characterization results confirmed that mesoporous cerium oxide was successfully assembled on the surface of Fe_3O_4@SiO_2 nanoparticles, and the synthesized adsorbent possessed a typical core-shell structure with a BET surface area of 195 m^2/g, accessible mesopores of 2.6 nm, and the saturation magnetization of 21.11 emu/g. The newly developed adsorbent had an excellent performance in adsorbing phosphate, and its maximum adsorption capacity calculated from the Langmuir model was 64.07 mg/g. The adsorption was fast, and the kinetic data could be best fitted with the pseudo-second-order kinetic model. The phosphate removal decreased with the increase of solution pH（2 to 10）, while the higher ionic strength slightly promoted the phosphate adsorption. The presence of Cl~– and SO^（2–）_4 could enhance the adsorption of phosphate whereas HCO~–_ 3 had interfering effect on the phosphate adsorption. The adsorption mechanism was studied by analyzing Zeta potential and FTIR spectroscopy, and the results indicated that the replacement of the surface hydroxyl groups by phosphate ions with the formation of inner-sphere complex played a key role in the phosphate adsorption. The spent adsorbent could be quickly separated from aqueous solution with the assistance of the external magnetic field, and the adsorbed phosphate could be effectively desorbed using a 1 mol/L NaOH solution.

Preparation of a novel magnetic resin for effective removal of both natural organic matter and organic micropollutants

A novel, bifunctional, hypercrosslinked, magnetic resin W2 was prepared using divinylbenzene （DVB） and glycidyl methacrylate （GMA） as comonomers in three steps （i.e., suspension polymerization, amination and post-crosslinking reactions）. To evaluate the adsorption of natural organic matter （NOM） and organic micropollutants （OMPs） on the obtained resin W2, two magnetic resins W1 （the precursor of W2 before post-crosslinking） and W0 （the precursor of W1 before amination） were chosen for comparison. The results indicated that W2 would be a promising material for the removal of both NOM and OMPs from aquatic environments.

Gas-assisted magnetic separation for the purification of proteins in batch systems

In this paper, gas-assisted magnetic separation （GAMS）, a technique that combines magnetic separation with flotation, was investigated for the potential large-scale separation of proteins, The GAMS process includes adsorption of target proteins and magnetic separation to recover protein-loaded magnetic particles from the dilute biosuspension with the assistance of bubbles, Microsized ethylenediamine- functionalized poly（glycidyl methacrylate） superparamagnetic microspheres （MPMs） and bovine serum albumin （BSA） were used as a model system. The feasibility of GAMS for capturing BSA-loaded MPMs from an appropriate medium was shown, High recovery of BSA-loaded MPMs was obtained by simple adjustment of the initial solution pH without extra detergents and antifoaming agents. The GAMS con- ditions were consistent with the adsorption conditions, and no proteins were desorbed from the MPMs during this process. Under the optimal conditions, the separation rate and recovery percentage reached 410 mL/min and 98% in 0.61 min, respectively. Conformational changes of BSA during the GAMS process were investigated by fluorescence spectroscopy and circular dichroism spectrometry,