Dry Biosolids Reuse as Costless Biodegradable Adsorbent for Cadmium Removal from Water Systems

• Main Authors: Tarek G. Ammari, Majida Al-Hadidi, Noor Al-Kharabsheh, Dima Khater, Saeid Abu-Romman
• Format: Article
• Language: English
• Published: Polish Society of Ecological Engineering (PTIE) 2021-05-01
• Series: Journal of Ecological Engineering
• Subjects: adsorption; cd-contaminated environment; untreated biosolids; intraparticle diffusion model; langmuir isotherm model
• Online Access: http://www.jeeng.net/Dry-Biosolids-Reuse-as-Costless-Biodegradable-Adsorbent-for-Cadmium-Removal-from,135901,0,2.html

The recycling of untreated dry biosolids, as costless biodegradable adsorbent for the removal of cadmium from aqueous phase was characterized. The adsorption of cadmium was reported to depend on initial pH, adsorbent dose, agitation time, and initial Cd concentration. The results of the batch experiments revealed that the maximum adsorption capacity of the untreated dry biosolids was 39.22 mg g-1 under optimum operating conditions (i.e. pH: 5, adsorbent dose: 2 g l-1, contact time: 16h). Adsorption reaches equilibrium after 16h, which can be attributed to both external surface adsorption (R2 = 0.86) and intraparticle diffusion (R2 = 0.98). The Langmuir isotherm model best described cadmium adsorption (R2 = 0.99) and the pseudo-second-order kinetic model was obeyed, suggesting that the mechanism involved was chemisorption. Biodegradability would make the recovery of adsorbed Cd an environmentally friendly process. Comparing the obtained findings with the related published results, it can be concluded that treating biosolids might be an unnecessary and costly procedure for recycling biosolids as an adsorbent for cadmium.