LaCl3 Research Articles

Use of lanthanum for water treatment A matter of concern?

Among several other eutrophication management tools, Phoslock®, a lanthanum modified bentonite (LMB) clay, is now frequently used. Concerns have been raised as to whether exposure to Phoslock®-treated water may lead to lanthanum accumulation/toxicity in both animals and humans.In the present experimental study, rats were administered lanthanum orally as either lanthanum carbonate, lanthanum chloride or Phoslock® at doses of either 0.5 or 17 mg/L during 10 weeks. Controls received vehicle. The gastrointestinal absorption and tissue distribution of lanthanum was investigated. Extremely strict measures were implemented to avoid cross-contamination between different tissues or animals.Results showed no differences in gastrointestinal absorption between the different compounds under study as reflected by the serum lanthanum levels and concentrations found in the brain, bone, heart, spleen, lung, kidney and testes. At sacrifice, significant but equally increased lanthanum concentrations versus vehicle were observed in the liver for the highest dose of each compound which however, remained several orders of magnitude below the liver lanthanum concentration previously measured after long-term therapeutic administration of lanthanum carbonate and for which no hepatotoxicity was noticed in humans.In conclusion, (i) the use of LMB does not pose a toxicity risk (ii) gastrointestinal absorption of lanthanum is minimal and independent on the type of the compound, (iii) with exception of the liver, no significant increase in lanthanum levels is observed in the various organs under study, (iv) based on previous studies, the slightly increased liver lanthanum levels observed in a worst case scenario do not hold any risk of hepatotoxicity.

Solvent extraction of lanthanum(III) from chloride and nitrate aqueous solutions with dioctyldiglycolamates of dioctylammonium and trioctylammonium

The extraction of lanthanum(III) from chloride and nitrate aqueous solutions in the systems involving new binary extractants based on N,N-dioctyldiglycolamic acid (HA) and di-n-octylamine (R2NH) or tri-n-octylamine (R3N) in toluene was studied. The compositions of the extracted species in the lanthanum extraction with dioctyldiglycolamates of dioctylammonium and trioctylammonium were investigated based on the analysis of the extraction isotherms. The formation of the extracted species, LaA3, in the extraction of La(III) from chloride aqueous solutions with binary extractants was indicated. The extraction of lanthanum from nitrate aqueous solutions proceeds with the formation of 1:1 complexes between the binary extractants and La(III). The extractability of lanthanum nitrate was found to be significantly greater than that of lanthanum chloride, owing to differences in the compositions of the extracted compounds.

Corrosion Electrochemical Behavior of Nickel in the LiCl–KCl Melt Containing Lanthanum Trichloride

The effect of temperature on the corrosion of nickel (N1) in the range from 500 to 800°C during testing in the salt melt of the eutectic mixture of lithium and potassium chlorides with the addition of lanthanum trichloride in the amounts from 0.5 to 2 mol % is studied. The nickel corrosion rate increases with temperature, and lanthanum chloride additives decrease the corrosion rate at 500–650°C (inhibition of the shielding type due to the subsequent chemical reaction). The corrosion potential of nickel is approximately –0.5 V relative to the silver chloride electrode at 500°C, insignificantly decreases with temperature, and is independent of the concentration of lanthanum chloride. To specify the mechanism of corrosion damage, current–voltage curves are recorded at lanthanum chloride contents of 0.5 and 2 mol % and sweep speeds of 10 and 20 mV/s. X-ray diffraction analysis and X-ray spectral microanalysis are used. The sweep speed exerts no effect on the irreversible electrochemical oxidation process, and the addition of lanthanum chloride increases the current density in the anodic region tenfold or more. A comparison of the corrosion rates obtained by gravimetric and chemical analytical methods suggests an electrochemical corrosion mechanism.

Extraction of Lanthanides with a Binary Extractant Based on Diglycolic Acid N,N-Dioctylamide and Trioctylamine

Extraction of lanthanum chloride and nitrate from neutral chloride and nitrate solutions with a binary extractant (R3NHA) based on an equimolar mixture of diglycolic acid N,N-dioctylamide and tri-n-octylamine was studied. It was shown that the extraction of lanthanum chloride with R3NHA proceeds by the mechanism of binary extraction of salts to give the LaA3 extractable compound in the organic phase. In the case of lanthanum nitrate extraction, complexes of a different composition are formed in the organic phase, with the ratio of the metal concentration in the organic phase to the initial concentration of the binary extractant being 1 : 1. The extractability of lanthanides in the system with this binary extractant increased with increasing atomic number of the metal.

Nanostructural and Electrical Properties of Al/Sn/La2O3 Nanocomposite as a Gate Dielectric of MOSFETs

Metal–oxide–semiconductor field-effect transistors (MOSFETs) have significant role on producing the electronic devices. The producers try to make the chips in smaller size so they need materials with high dielectric constant. Here, in this research, Al/Sn/La2O3 will introduce as a material with higher dielectric constant and less defections. In this research, Al/Sn/La2O3 nanostructure was prepared by sol–gel and spin-coating methods. Lanthanum chloride (LaCl3·7H2O), cetyltrimethylammonium bromide, ammonia (25%), aluminum tri-sec-butylate (C12H27AlO3), acetyl acetone (C2H5O8), isopropyl alcohol (C3H8O), Tin (II) chloride (SnCl2) and H2O were used to synthesize Al/Sn/La2O3. Structural properties and surface morphology of nanocrystallites were investigated by X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, atomic force microscopy and Fourier-transform infrared radiation, respectively. Electrical properties were determined with metal–dielectric–semiconductor through capacitance–voltage (C–V), the hysteresis curve and current density–voltage (J–V). The conduction mechanism was measured in the temperature range of 330 K < T < 410 K and in the electrical field < 0.12 MV cm−1, and the results showed ohmic emission. A thermal excited model was proposed to explain the mechanism of ohmic conduction current. The highest value of dielectric constant (k) for Al/Sn/La2O3 structure was 33 at T = 250 °C with almost amorphous structure. The result showed that $$ \frac{{I_{\text{on}} }}{{I_{\text{off}} }} $$ of Al/Sn/La2O3 structure was ~ 1.3. The leakage current and capacitance–voltage of Al/Sn/La2O3 nanocomposite for the sample calcined at T = 250 °C showed that this sample can be good enough for using as a gate dielectric of MOSFETs.

Immobilization of Copper from Aqueous Solution and Contaminated Sediment Using Modified Clinoptilolite

The efficiency and mechanism of modified clinoptilolites immobilizing Cu from aqueous solutions and contaminated sediments were investigated. The results showed that the clinoptilolite modified by lanthanum chloride (LaCl3) at a particle size of 0.5–1.0 mm could remove 65% of Cu2+ from 100 mg L−1 of Cu2+ solutions at the sorbent:solution mass ratio of 1:100. The equilibrium data fitted well to the Langmuir isotherm model with a maximum adsorption capacity of 21.09 mg Cu2+ g−1 at 25 °C. The Dubinin–Radushkevich adsorption model indicated that the adsorption of Cu2+ by modified clinoptilolite can be identified as chemisorption. The pseudo-second-order model could well represent the kinetics of the adsorption. The results of toxicity characteristic leaching procedure (TCLP) and Community Bureau of Reference (BCR) sequential extraction procedure showed that the modified clinoptilolite could reduce the leaching of Cu in the sediment and effectively transform Cu from the acid extractable or reducible fractions to the oxidizable or residual fractions. The presented work showed that the modified clinoptilolite holds great potential to remove Cu2+ from water, and to stabilize Cu-contaminated sediment.

Novel lanthanum-modified activated carbon derived from pine cone biomass as ecofriendly bio-sorbent for removal of phosphate and nitrate in wastewater

A low-cost and high-efficiency adsorbent was developed by chemical activation of pine cone biomass with lanthanum chloride (La-PC) and applied for the simultaneous removal of phosphate (P) and nitrate (N) in aqueous solution. Equilibrium and kinetic experiments were performed to investigate the effects of operating conditions such as solution pH, coexisting ions, and initial concentration on the removal of P and N. The maximum adsorption capacities using La-PC were 68.2 and 46.6 mg g−1 for P; 25.8 and 21.4 mg g−1 for N, in single- and mixed system, respectively. Adsorption isotherm and adsorption kinetic studies showed that the Langmuir isotherm and second-order model were well fitted, indicating that the adsorption of P and N was dominated by a homogeneous and chemisorption. The presence of other anions such as SO42−, HCO 3 −, and Cl– was slightly effected for removal of P and N. In addition, the regeneration of the adsorbent could be easily achieved and desorption efficiencies after three cycles were 89.4 and 76.5% for P and N, respectively. Based on the results, La-PC would be utilized as a promising material for removal of nutrients from water from aqueous solution.

Foliar-applied lanthanum chloride increases growth and phosphorus acquisition in phosphorus-limited adzuki bean seedlings

Lanthanum, a rare earth element, is used in agriculture and forestry to promote plant growth and productivity. We aimed to investigate its role in altering the roots and alleviating P deficiency in the adzuki bean Vigna angularis. The adzuki bean variety “Jin No. 5” was pre-cultivated in sand. Fourteen-day-old seedlings were sprayed twice with 0.4 mM LaCl3 solution. Next, we treated the seedlings with half-strength Hoagland solution containing P reduced to 1% of its original concentration (P-deficient); P reduced to 5% of the original (P-marginal); and unadjusted solution (P-sufficient). We measured plant growth, root structure, root hydraulic conductivity, P content, gas exchange, and photosynthetic pigment levels in all groups. LaCl3 application significantly increased leaf P concentration, effectively improving the P uptake efficiency of roots, shoots, and leaves under severe P stress. Root morphology and acid phosphatase (APase) activity varied significantly in response to LaCl3 under low-P stress. A greater leaf area, gas exchange ability, chlorophyll content, and carotenoid content were observed in the presence of LaCl3 under P-marginal stress. The application of LaCl3 can promote growth and P acquisition in adzuki beans under P limitation by inducing changes in root morphology, APase activity, and hydraulic conductivity.

Cloning and expression analysis of calmodulin gene from Pinellia ternate

According to the data of Pinellia ternate transcriptome,two calmodulin genes were cloned and named as Pt Ca M1 and PtCa M2 respectively. The results of bioinformatics analysis showed that Pt Ca Ms genes contained a 450 bp open reading frame,encoding149 amino acids.The identity of the coding sequences was 80%,and the identity of amino acids sequence was 91%. Pt Ca Ms genes contained EF-hand structure domain,belonging to the Ca M families. The Real-time PCR analysed the expression patterns of Pt Ca Ms in different tissues and different treatments. RESULTS:: showed that Pt Ca M1 and Pt Ca M2 gene were the highest expression level in tuber. Under Ca Cl2 treatment,the expressions of Pt Ca Ms were significantly higher than the control. Under EGTA,La Cl3 and TFP treatments,the expression level of Pt Ca Ms decreased gradually. In this study,the Pt Ca Ms gene were successfully cloned from P. ternate,which laid a foundation for the functional characteristic of Pt Ca Ms gene and the synthesis of alkaloids from P. ternata for further study.

The effects of electrostatic correlations on the ionic current rectification in conical nanopores.

Ion-ion electrostatic correlations are recognized to play a significant role in the presence of concentrated multivalent electrolytes. To account for their impact on ionic current rectification phenomenon in conical nanopores, we use the modified continuum Poisson-Nernst-Planck (PNP) equations by Bazant et al. Coupled with the Stokes equations, the effects of the EOF are also included. We thoroughly investigate the dependence of the ionic current rectification ratios as a function of the double layer thickness and the electrostatic correlation length. By considering the electrostatic correlations, the modified PNP model successfully captures the ionic current rectification reversal in nanopores filled with lanthanum chloride LaCl3 . This finding qualitatively agrees with the experimental observations that cannot be explained by the standard PNP model, suggesting that ion-ion electrostatic correlations are responsible for this reversal behavior. The modified PNP model not only can be used to explain the experiments, but also go beyond to provide a design tool for nanopore applications involving multivalent electrolytes.

Effect of Yttrium (20%) doping on mechanical properties of rare earth nano lanthanum phosphate (LaPO4) synthesized by aqueous sol-gel process

In this study, Nascent Lanthanum Phosphate (LaPO4) and LaPO4 with 20% reinforced Yttria (Y2O3) precursor ceramic powder was synthesized through aqueous Sol-gel route, where theLaPO4 and LaPO4/Y2O3 powder was sourced from Lanthanum chloride (LaCl3) and orthophosphoric acid (H3PO4). By sintering the precursor powder at 1400 °C for 2 h, a relatively high-density composite material of LaPO4 (97.4%) and LaPO4/Y2O3 (98.4%) were fabricated. Through X-ray powder diffraction (XRD) experiment, the results revealed that LaPO4 and LaPO4/Y2O3 electrolyte samples sintered at 1400 °C for 2 h is impurity free and thereby elemental composition of the powders is also verified. Further, a small quantity of LaP2 and La2O3elements formed during the synthesis of LaPO4 was found to contribute more on corrosion resistance and high withstanding capacity of the material. 26% of YPO4 formed due to a chemical reaction between Yttrium and Lanthanum made this composite a suitable candidate material for high-temperature applications. Various mechanical characterization tests such as micro-hardness, flexural strength, and compression capacity were studied, where the microscopic analysis provided comprehensive information about both transgranular and intergranular types of failure on the fractured regions of LaPO4 and LaPO4/Y2O3 material. The MicroVicker'shardness of LaPO4 and composite was found to be 5 GPa and 5.2 GPa, respectively. When compared with the nascent sample, on an average, 22% reduction in flexural strength and a 1.05% increase in Young's modulus are observed for the high-density composite.

Synthesis and characterization of lanthanum chloride doped L-alanine maleate single crystals

Doping of non-linear optical materials by different elements and compounds is the common method to tune the various properties of these materials. In this work we report single crystals of undoped and lanthanum chloride (LaCl3) doped L-Alanine Maleate (LAM) grown by slow evaporation solution growth method at room temperature. From the single crystal X-ray diffraction analysis it was observed that both undoped, 1 and 2 mol% LaCl3-doped LAM samples were crystallized in the orthorhombic crystal system with P212121 space group. The optical properties of the LAM single crystals investigated by UV–VIS/NIR spectrometer revealed that the crystals were transparent in the wavelength range of 300–1100 nm. The band gap of the undoped and LaCl3 doped LAM single crystals were found to be 4.13 eV. Energy dispersive X-ray analysis confirmed the incorporation of LaCl3 in LAM single crystals. Simultaneous TG/DT analysis revealed the thermal stability of the samples below 145 °C. The second harmonic generation efficiency of the samples was analyzed by Kurtz-Perry powder technique and compared with the standard KDP crystal.

Lanthanum chloride induces neuron damage by activating the nuclear factor-kappa B signaling pathway in activated microglia.

Lanthanum is a rare earth element which can have adverse effects on the central nervous system (CNS). However, the mechanisms of these effects are not fully understood. The activated microglia plays an important role in the pathogenesis of neurodegenerative diseases and thus could be involved in mediating the toxic effects of lanthanum on the CNS. Nuclear factor-kappa B (NF-κB) is a critical nuclear factor which regulates the expression of inflammatory mediators in the activated microglia. This study investigated the effects of lanthanum chloride (LaCl3) on the NF-κB signaling pathway and explored the relationship between the microglia activation and neuron damage induced by La in vitro. The results showed that BV2 microglial cells treated with 0, 0.05, 0.1 or 0.2 mM LaCl3 could up-regulate the expression of Iba1 protein, a marker of microglia activation, and of p-IKKαβ and p-IκBα in a dose-dependent manner. La could also increase the translocation of the NF-κB p65 subunit from the cytosol into the nucleus, and then elevate the production of NO, TNF-α, IL-1β, IL-6 and MCP-1 by BV2 microglial cells. In a neuron-microglia co-culture system, BV2 microglia treated with LaCl3 resulted in a significant increase of the rates of neuron apoptosis. Conversely, the pre-treatment with PDTC (an inhibitor of the NF-κB signaling pathway) could inhibit the release of inflammatory cytokines and reduce the number of apoptotic neurons caused by La. These findings suggested that the neuron injury induced by LaCl3 might be related to the abnormal activation of microglia, which could remarkably increase the expression and release of pro-inflammatory cytokines via activating the NF-κB signaling pathway.

Role of Ca2+ in phenolic compound metabolism of barley (Hordeum vulgare L.) sprouts under NaCl stress.

The literature on the role of calcium ion (Ca2+ ) in relation to phenolic compounds metabolism and related enzymes activities remains controversial. It is still unclear whether Ca2+ affects phenolic compounds content of barley sprouts. This study investigated the role and function of Ca2+ in phenolic compound metabolism of barley (Hordeum vulgare L.) sprouts under sodium chloride (NaCl) stress. Calcium chloride (CaCl2 ) significantly improved total calcium and calmodulin (CaM) contents as well as Ca2+ concentration, and enhanced phenolic compound accumulation by regulating the gene, protein expression and the activities of enzymes related to phenolics biosynthesis. Specifically, CaCl2 significantly increased the activities of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), 4-coumarate coenzyme A ligase (4CL) and ferulic acid 5-hydroxylase (F5H) by up-regulating the corresponding protein expression. The activity of p-coumaric acid 3-hydroxylase (C3H) decreased during germination while caffeic acid O-methyltransferase (COMT) increased initially and then decreased, which was consistent with the changes in gene and protein expression under CaCl2 treatment. Conversely, lanthanum(III) chloride (LaCl3 ), ethylene glycol tetraacetic acid (EGTA) and 2-aminoethoxydiphenyl borate (2-APB) induced opposite effects. Decreased calcium and CaM contents and Ca2+ concentration were observed, and fluctuation change of relevant gene and protein expressions and PAL, C4H, 4CL, C3H, COMT and F5H activitives were also detected. Calcium ion played an important role for mediating NaCl stress-induced phenolics accumulation in barley sprouts. It required both Ca2+ influx and release from apoplast and intracellular stores, respectively. © 2019 Society of Chemical Industry.

Electrosurface properties of Na-bentonite particles in electrolytes and surfactants solution

The results of study of the impact of pH, alkali metal, calcium and lanthanum chlorides, alkali metal sulphates as well as sodium dodecyl sulphate and cetyltrimethylammonium bromide on the zeta-(ζ) potential and electrical conductivity of suspensions containing Na-bentonite particles are presented. The behaviour of the suspension in an external electric field can be summarized as follows: ζ-potential of particles show low sensitivity to pH and they display relatively high ζ values (from −35 mV to −52 mV) both in water and in supporting electrolytes solution; the ζ(C) dependencies for RbCl and CsCl are characterized by a constant ζ-potential at C 10−5–10−3 mol/L, and for LiCl, NaCl and KCl by a maximum at C 10−3–10−2 mol/L; the relative position of the ζ(C) curves corresponds to the regular Hofmeister series; ζ-potential in alkali metal sulphates solutions was found to be higher compared to that for chlorides at equivalent concentration of salts; addition of electrolytes with bi-and trivalent counter-ions or cationic surfactant caused a substantial reduction in ζ and surface charge reversal, respectively; a regular decrease in the surface conductivity of particles was measured while moving from LiCl to CsCl in the lyotropic series.The observed regularities are explained by accounting for two opposite trends related to the polarization of the electrical double layer (EDL) in the external electric field (increase of ζ-potential at low concentration) and the effect of the EDL compression (decrease of ζ-potential at high concentration) as well as the increase in filling up the Stern-layer with alkali metal ions as their radius increases. We connect the bigger ζ-potential values for sulphates compared to that for chlorides with dehydration effect of sulphate co-ions which results in the thinning the surface hydrate layer and shift of the shear plane toward the surface. The “electrokinetic charge” calculated from the ζ-potential comprises a small part of the cation exchange capacity of the mineral, i.e. the counter-ions are located mainly in the hydro-dynamically immobile part of the EDL.

Effect of rare earth surface modification of carbon nanotubes on enhancement of interfacial bonding of carbon nanotubes reinforced epoxy matrix composites

Rare earth (RE) lanthanum chloride was used to modify carbon nanotubes (CNTs) to obtain rare earth modified carbon nanotubes (RECNTs). The modified CNTs were characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results show that RE has a significant effect on improving the surface activity of carbon nanotubes. Through the chemical function of RE, the CNTs were successfully grafted with functional groups such as amino groups and carboxyl groups. This method can be used to connect any oxygen- or nitrogen-containing functional groups to the CNTs according to actual needs. Then, the modified CNTs were incorporated into epoxy resin (EP) to prepare composite (REACNTs/EP). The mechanical properties of the composites were tested by Zwick/Roell Z100 and Zwick/Roell Z20 test machine, and the tensile fractural sections were analyzed by scanning electron microscopy, and compared to the composites prepared with untreated CNTs (CNTs/EP), acidified carbon nanotubes (ACNTs/EP), acidification and RE synergistic modification of carbon nanotubes (REACNTs/EP). The results show that the ultimate tensile strength and tensile modulus of RECNTs/EP were increased by 33.9%, 73.7%, respectively, compared with pure EP, while the properties of REACNTs/EP were increased by 50.7%, 90.9%, indicating that RE has excellent effect on improving the mechanical properties of carbon nanotube-reinforced composites.

Chloride influence on the reaction mechanism of lanthanum hexaboride

Lanthanum hexaboride (LaB6) is well-known for its established physical properties, such as its incredible hardness and thermionic emission. On the nanoscale, LaB6 is gaining in popularity as an IR-active plasmonic material. However, while researchers are learning how to control the synthesis and tune the plasmon of these particles to meet desired application needs, very little is known about the basic chemical mechanism behind its formation. The assumptions that high temperatures and pressures were required to drive the reaction of LaB6 have been proven false in recent years, raising even more questions with regard to what conditions are really mandatory when designing a synthetic protocol. This work reports the use of in-situ diffraction experiments to help determine how lanthanum chloride and sodium borohydride precursors interact with and change one another in the LaB6 synthesis, and highlights the importance of the halogen in the reaction scheme. In understanding the driving forces and mechanism behind LaB6 formation, it may be easier for researchers to predict and control the particle shape, size, and even electronic properties of their hexaboride materials.

Oil‐impregnated monomer casting nylon composites reinforced by graphene oxide and Lanthanum(III) chloride

Oil‐impregnated monomer casting (OMC) nylon composites reinforced by graphene oxide and Lanthanum(III) chloride (LaCl3) were prepared by anionic ring‐opening polymerization in the presence of sodium hydroxide catalyst and toluene‐2, 4‐diisocyanate cocatalyst. The cross‐linked GO was formed by the coordination and electrostatic interactions between La3+ and the carboxyl on the edge of GO, which resulted in an obvious reinforcement for the OMC nylon composites. The effects of different rare earth contents on mechanical and tribological properties of the composites were carried out. The results showed that the composites exhibited excellent comprehensive properties when 0.01 wt% GO and 0.007 wt% LaCl3 were incorporated in OMC nylon. The elastic modulus, flexural strength, flexural modulus, compressive strength, notched impact strength, and elongation‐at‐break for the OMC nylon/GO/LaCl3 composites increased by 6.1, 9.9, 18.2, 7.2, 40.8, and 24.4%, respectively, and the tensile strength was slightly improved. In addition, the abrasion quantity was reduced. POLYM. ENG. SCI., 59:982–988, 2019. © 2019 Society of Plastics Engineers

Preparation of La2O3 by ion-exchange membrane electrolysis of LaCl3 aqueous solution

The ion-exchange membrane electrolysis technology was applied inventively in the preparation of lanthanum hydroxide, after calcination, lanthanum oxide was obtained eventually. The effect of the concentration of lanthanum chloride solution on electrolytic product was mainly investigated. The phase composition, micro morphology, particle size and chlorine content of the product were characterized, respectively. Under the conditions of this work, the product that forms by electrolysis of LaCl3 aqueous solution directly is La(OH)3. When the initial concentration of LaCl3 changes from 0.1 to 0.5 mol/L, the current efficiency of La(OH)3 increases from 60% to 85%, the product roasted at 800 °C for 1.5 h is La2O3, whose median particle size (D50) is 10–20 μm, the mass fraction of chloride ion is less than 0.02 wt%. Additionally, the prepared La2O3 particles are porous and non-spherical particles, which are composed of small crystals with sheet structure.

Lanthanum chloride improves maize grain yield by promoting photosynthetic characteristics, antioxidants enzymes and endogenous hormone at reproductive stages

Despite an increase in application spectrum of rare earth elements in agriculture, all studies show that the suitable accumulation of rare earth elements can improve the crop seedling growth, but there is little research about REEs on physiological mechanisms of crops at reproductive stages. Therefore, this study was conducted to examine the possible potential benefits of lanthanum chloride (LaCl3) on the senescence and grain yield responses of maize. In this study, maize seeds were pre-treated by soaking with LaCl3 at the concentrations of 0 (CK), 400 (LC1), 800 (LC2) and 1200 (LC3) μmol/L, to evaluate its effect on the green leaf area, chlorophyll contents, photosynthesis, antioxidants, endogenous hormones in the later crop growth stages. The results show that LC1 and LC2 treatments evidently increase green leaf area, above ground dry biomass, accompanied by a distinct increase in the chlorophyll contents, and photosynthetic capacity, which promote the ear characteristics and grain yield of maize. In addition, LC1 and LC2 treatments simultaneously increase the activities of antioxidants, including superoxide dismutases, catalases, peroxidases, soluble protein, and enhanced levels of auxin, gibberellin and zeatin, following a dose-response tendency. Themalondialdehyde and abscisic acid levels transiently increase with the progression in the growth stage of the crop but are markedly decreased at LC1 and LC2 treatments, while LC3 treatment has no significant effect on malondialdehyde and even accelerates the accumulation of abscisic acid in maize leaves. Our data suggest that seed priming with LaCl3 at a suitable concentration range (400–800 μmol/L) can prolong the functional periods of leaves, increase photosynthetic capacity, enhance antioxidant activity, and alter endogenous hormone levels at reproductive stages, resulting in delaying leaf senescence rate and increasing yield. However, the moderate concentration of LaCl3 for maize is LC2 (800 μmol/L), and can be effectively used to improve grain yield of maize.