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• Porous hexagonal boron nitride (p-BN) was employed for Ni(II) scavenging. • The p-BN displayed a high removal rate to Ni(II). • The p-BN exhibited an adsorption capacity to Ni(II). • Interaction between hydroxyl-O and electron-deficient B is the main mechanism. Intending to remove Ni(II) from wastewater, porous p-BN was employed to recovery Ni(II) by batch and X-ray photoelectron spectroscopy technique. The performances and mechanism of p-BN for Ni(II) sorption had been studied by diverse characterization technologies. The kinetic data was calculated to conform a pseudo-second-order model, and isotherm data fitted to a Freundlich equation. We obtained a high removal rate and a high adsorption capacity. A possible mechanism can be expressed from XPS results. The surface of p-BN is B OH/B NH 2 enriched and exhibits a weak alkalinity. When p-BN contact with Ni(II) solution, the hydroxide ions releases from the surface while there is a formation of B O⋯Ni; the small group of B O⋯Ni is acting with hydroxide ions, thereby forming B O⋯Ni(OH) 2 and continuously adsorbs Ni(II) to form B O⋯Ni(OH)ONi(OH) like as precipitated nucleus. Then, due to the interaction of hydroxyl-O with electron-deficient B, the veil-like Ni(OH) 2 generated from precipitated nucleus evenly attaches to p-BN. The bonding state of Ni(II) on p-BN by XPS spectra revealed that the process of adsorbing Ni(II) onto p-BN was chemisorption through the formation of Ni(OH) 2 and the interaction between hydroxyl-O and electron-deficient B. The analyses implied that p-BN is a promising candidate for recovery of Ni(II) from wastewater. [ABSTRACT FROM AUTHOR]

• Novel composite material of g-C 3 N 4 decorated FeS was designed and prepared. • The adsorption capacity for U(VI) was 917.1 mg/g at pH = 6.0. • The adsorption isotherm for U(VI) was described by the Freundlich model. In this study, a novel graphitic carbon nitride decorated nanoscale FeS composite (g-C 3 N 4 /FeS) was prepared and performed for the removal of U(VI) in aqueous system. Results revealed that g-C 3 N 4 /FeS had excellent adsorbability, which can reach 917.1 mg/g at 303 K. In addition, the effects of pH, adsorbent dose, contact time and initial U(VI) concentration were investigated by batch experiments. Experimental results indicated the removal of U(VI) on g-C 3 N 4 /FeS was strongly dependent on pH, and the adsorption capacity reached the maximum at pH = 6.0. Kinetics studies under different conditions indicated the removal of U(VI) on g-C 3 N 4 /FeS fitted the pseudo-second-order model well. Furthermore, the adsorption isotherms of U(VI) on g-C 3 N 4 /FeS fitted with Freundlich models well. These results demonstrated that g-C 3 N 4 /FeS could be the promising alternative material for environmental remediation. [ABSTRACT FROM AUTHOR]