Linz-Donawitz(LD) slag Geopolymer(LDSGP), a porous aluminosillicate geopolymeric adsorbent, has been synthesized from steel plant LD slag for efficient removal of Zinc(II) ions from wastewater, thus presenting a solution for converting industrial waste to adsorbent for wastewater treatment. The colloid paste of raw LD slag and the alkaline activator (10 M NaOH + sodium silicate (1: 1 w/w)) has been cured for 3 days at low temperature to geopolymerize the calcium oxide rich LD slag. The BET surface area of LDSGP adsorbent (30.84 m(2)/g) has improved considerably compared to raw LDS (4.85 m(2)/g) and the FESEM and HRTEM images reveal the presence of micropetal and cauliflower like structures at outer surface of the adsorbent particles. The mesoporous nature of LDSGP adsorbent can be understood by analyzing N-2 adsorption-desorption and pore size distribution plot. The PXRD pattern of LDSGP adsorbent powder confirms the presence of Ca2SiO4 and Ca3SiO5 in the geopolymeric matrix. Langmuir isotherm model correlates the batch adsorption data of Zn2+ ions onto LDSGP particles at 298 K, 308 K and 318 K. The maximum Zn2+ ions adsorption capacity of LDSGP is 86 mg/g at 318 K. The adsorption kinetic data is correlated with pseudo-second-order model indicating chemisorption of Zn2+ ions onto LD slag geopolymeric powder adsorbent. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.