Comparison of toxicity between lanthanum oxide nanoparticles and lanthanum chloride

Due to the wide application of rare earth elements,lanthanum(La) is gradually accumulated in our living environment.Lanthanum can enter the body through a variety of routes,which has a series of effects on various systems.As a consequence,the safety of lanthanum deserves our attention.This study aims to compare the toxicity of lanthanum oxide nanoparticles(La_(2)O_(3) NPs) and lanthanum chloride(LaCl_(3)) and enrich the toxicity evaluation of lanthanum.Therefore,a 30 d intragastal experiment was conducted.C57BL/6j mice were given by La_(2)O_(3) NPs solution and LaCl_(3) solution respectively at doses of 0,30,60 and120 mg/kg BW(lanthanum content).The results show that,compared with the control group,both La_(2)O_(3)NPs and LaCl_(3) can reduce the body weight of female mice in the high-dose group,but for male mice,the high-dose La_(2)O_(3) NPs solution can increase the body weight,while LaCl_(3) has the opposite effect.The coefficients of liver,kidney,heart,lung,uterine and ovaries increase first and then decrease with the exposure dose,but testes and epididymides coefficient keep increasing with the exposure of LaCl_(3) and La_(2)O_(3) NPs.La_(2)O_(3) NPs and LaCl_(3) can reduce the concentration of triglycerides(TG) and increase the level of low density lipoprotein(LDL),but the effect of La_(2)O_(3) NPs is more obvious.La_(2)O_(3) NPs and LaCl_(3) can reduce the concentration of malondialdehyde(MDA),increase the total antioxidant capacity(T-AOC)and enhance the activity of catalase(CAT),but LaCl_(3) has more obvious protective effects on oxidative stress.La_(2)O_(3) NPs and LaCl_(3) have potential risks to liver,and the toxicity of La_(2)O_(3) NPs might be higher than that of LaCl_(3).

Catalytic action of rare earth oxide(La_(2)O_(3),CeO_(2),Pr_(6)O_(11))on electrochemical oxidation of activated carbon in molten KOH-NaOH

The oxidation of anode carbon fuel directly affects the electrochemical performance of molten hydroxide direct carbon fuel cell(MHDCFC).In general,the anode carbon fuel can be oxidized at high temperature,thus the direct carbon fuel cell(DCFC)can show great electrochemical performance.In this study,rare earth oxides(La_(2)O_(3),CeO_(2),Pr_(6)O_(11))were prepared by the method of precipitation.Activated carbon was prepared by pretreatment of lignite.Rare earth oxides and activated carbon were mixed as anode carbon fuel,and rare earth oxides were used to catalyze the electrochemical oxidation of anode carbon fuel.The results show that CeO_(2)has better electrocatalytic activity compared with La_(2)O_(3)and Pr_(6)O_(11) in the MHDCFC.The electrochemical test results show that the current density(at 0.4 V)increases from 81.02 to 112.90 mA/cm^(2)and the maximum power density increases from 34.78 to 47.05 mW/cm^(2)at 450℃,when the mass fraction of CeO_(2)is increased from 0 to 40%.When the mass fraction of CeO_(2)is 30%,the current density(82.55 mA/cm^(2)at 0.4 V)at 400℃is higher than that(81.02 mA/cm^(2)at 0.4 V)without CeO_(2)at 450℃.The electrochemical oxidation mechanism of CeO_(2)catalyzed anode carbon fuel is discussed.