Hendrini Pujiastuti
Universitas Sultan Ageng Tirtayasa

Published : 2 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 2 Documents
Search

Coconut Shell Activated Carbon as a Sustainable Adsorbent for Gold Recovery from Aqueous Leaching Solutions: A Review Heri Heriyanto; Nufus Kanani; Hendrini Pujiastuti; Rusdi Rusdi
World Chemical Engineering Journal VOLUME 10 NO. 1 JUNE 2026
Publisher : Chemical Engineering Department, Engineering Faculty, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62870/wcej.v1i1.40169

Abstract

Gold recovery from dilute hydrometallurgical process liquors has become a strategic priority within circular-economy resource management and responsible precious-metal stewardship. Activated carbon dominates gold capture in industrial circuits, particularly in alkaline cyanide systems where the anionic dicyanoaurate complex, Au(CN)₂⁻, is the principal dissolved species; however, economic constraints and sustainability pressures have stimulated growing interest in biomass-derived alternatives. This review critically synthesizes the evidence base for coconut shell activated carbon as a sustainable, high-performance adsorbent for gold recovery from aqueous leaching media, encompassing feedstock selection, activation pathways, pore architecture, adsorption mechanisms, solution speciation in cyanide and cyanide-free systems, and kinetic and equilibrium modelling. The literature demonstrates that gold removal efficiencies of 87–89% are attainable under optimized cyanide-leachate conditions — alkaline pH, gentle agitation, 1.25 g/L adsorbent dose, and approximately 3 h contact — compatible with real processing environments. Feedstock maturity and activation protocol decisively govern adsorption rate, loading capacity, and mechanical integrity, confirming that material quality must be actively engineered. Equilibrium behaviour conforms to the Freundlich isotherm, reflecting energetically heterogeneous surface sites, while kinetics follow pseudo-first-order dynamics with intraparticle diffusion as a co-limiting resistance. Coconut shell activated carbon holds genuine promise as a low-cost, environmentally responsible adsorbent, contingent on deliberate optimization of pore structure, surface chemistry, elution efficiency, regeneration durability, and real-leachate selectivity.
Comparative Evaluation of HETP in Ethanol–Water Distillation Using the Fenske and McCabe–Thiele Methods under Ideal and Non-Ideal Conditions Hendrini Pujiastuti; Sarah Rafidah; Heri Heriyanto; Nufus Kanani; Vitro Rahmat; Claudia Shinta Wibowo; Haroki Madani
World Chemical Engineering Journal VOLUME 10 NO. 1 JUNE 2026
Publisher : Chemical Engineering Department, Engineering Faculty, Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62870/wcej.v1i1.40222

Abstract

Height Equivalent to a Theoretical Plate (HETP) is widely used to assess mass-transfer performance in packed distillation columns by expressing the packing height needed to provide the separation effect of one ideal stage. Therefore, reliable HETP estimation is important for interpreting column efficiency and for supporting distillation-column design and evaluation.. This study evaluates HETP determination in an ethanol–water distillation system using three approaches, namely the Fenske method, and the McCabe–Thiele method under ideal and non-ideal conditions. The experiment was conducted under total reflux to obtain minimum theoretical stages, while ethanol composition in the feed, distillate, and residue was determined from a standard curve relating corrected refractive index to ethanol mole fraction. The feed was prepared from equal volumes of ethanol and distilled water, each 150 mL. The calibration data were represented by a polynomial equation with R² = 0.997. From this relationship, the ethanol mole fractions were estimated as 0.1949 in the feed, 0.3339 in the distillate, and 0.1588 in the residue.. Using these composition values, the Fenske calculation gave 1.1775 theoretical stages with an HETP of 281.7535 cm/plate. The ideal McCabe-Thiele construction resulted in 1.0501 stages and an HETP of 998.8858 cm/plate, whereas the non-ideal McCabe-Thiele construction produced 0.3894 stages and a negative HETP value of -81.8839 cm/plate..These discrepancies indicate that HETP determination is highly sensitive to the selected stage-estimation model and to the reliability of experimental composition data, particularly when refractive-index-based residue measurements are used. The physically unrealistic negative HETP obtained from the non-ideal McCabe–Thiele approach further emphasizes the need for critical evaluation of model assumptions and experimental uncertainty when interpreting HETP values for laboratory-scale ethanol–water distillation.