Soils consist of various components that can influence significantly heavy metal control in the environment. Understanding the adsorption characteristic of soil is important in combating pollution problems around farming areas. This work explored the sorption characteristics and retention of Pb and Cd by soils from Isu Aniocha farming area in Anambra state, Nigeria. The influence of temperature, metal concentration, pH and time on the sequestration of Pb 2+ and Cd 2+ was evaluated by batch sorption technique. Physicochemical properties of the soil were determined by standard techniques. Isotherm evaluation was performed by the Langmuir, Tempkin and Freundlich models. Pb (II) ion showed higher adsorption characteristics on the soil than Cd (II) from the maximum uptake capacity obtained. The maximum adsorption values for Pb range from 38.46 to 47.62 mg/g, while that for Cd range from 30.30 to 41.46 mg/g. Kinetic evaluation was conducted by the application of the pseudo first order, pseudo second order and intraparticle diffusion rate equations. The best fit on metal removal on the soils was achieved with the pseudo-second order model. The results showed that soils from a farming area can be effective in decreasing heavy metals pollution, especially Pb and Cd ions from solution phase.

Magnetic skyrmions, which are topologically distinct magnetic spin textures, are gaining increased attention for their unique physical properties and potential applications in spintronic devices. Here we present a design strategy for skyrmion host candidates based on combinations of magnetic spin, asymmetric building units having stereoactive lone-pair electrons, and polar lattice symmetry. To demonstrate the viability of the proposed rational design principles, we successfully synthesized a Fe­(IO3)3 polycrystalline sample and single crystals by using a new simplified low-temperature pathway, which is experimentally feasible for extending materials growth of transition metal iodates. Single crystal X-ray and powder synchrotron X-ray diffraction measurements demonstrated that Fe­(IO3)3 crystallizes in the polar chiral hexagonal lattice with space group P63. The combined structural features of the macroscopic electric polarization along the c-axis stemming from the coalignment of the stereoactive lone-pairs of the IO3 – trigonal pyramid and the magnetic Fe3+ cation residing on the 3-fold rotation axis were selected to promote asymmetric exchange coupling. We find evidence of a predicted skyrmion phase at 14 K ≤ T ≤ 16 K and 2.5 T ≤ μ0 H ≤ 3.2 T driven by a Dzyaloshinskii–Moriya (DM) interaction, a conclusion supported by the appreciable DM exchange and the zero-field spiral antiferromagnetic ground state of Fe­(IO3)3 deduced from neutron diffraction experiments. The associated magnetic modulation wavelength of the putative skyrmions is expected to be short ∼18 nm, comparable to the period of the DM-driven incommensurate order. This work links stereoactive lone-pair electron effects to enhanced DM interaction, demonstrating a new approach for chemical guidelines in the search for skyrmionic states of matter.

, crystal structure, computational analysis and biological properties of 1-(4-chlorobenzoyl)-3-[2-(2-{2-[3-(4-chlorobenzoyl)-thioureido]-ethoxy}ethoxy)ethyl]thiourea and its Ni(II) and Cu(II) complexes