Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was reviewed?
This review article, Biosorption of Heavy Metals, examined biological methods for the removal of toxic heavy metals from wastewater. It systematically summarized research on the use of biosorbents such as bacteria, algae, fungi, yeast, agricultural wastes, and industrial byproducts for metal sequestration. The review covered removal mechanisms, sorption isotherms, sorption kinetics, influencing parameters (pH, temperature, concentration, surface chemistry), and economic aspects of biosorption technologies. Its scope extended to toxic heavy metals such as lead, cadmium, chromium, mercury, arsenic, and nickel, emphasizing the potential of biosorption as an economical and environmentally friendly alternative to conventional remediation techniques
Who was reviewed?
The review synthesized findings from studies published between 2000 and 2013, encompassing laboratory and pilot-scale evaluations of biosorbents from microbial, algal, fungal, and plant sources. It drew on evidence from a wide range of industrial applications—including effluents from electroplating, mining, leather, fertilizer, dyeing, and metallurgical industries—where heavy metal pollution was prevalent. The reviewed works also highlighted regulatory perspectives by citing health and environmental impacts of metal exposure and limitations of conventional treatment methods, thereby linking academic research to applied industry needs
Most important findings
| Topic | Key Findings |
|---|---|
| Limitations of conventional technologies | Physical and chemical methods such as precipitation, ion exchange, and membrane filtration are often costly, produce toxic sludge, and are less effective at low metal concentrations. |
| Definition and mechanism of biosorption | Biosorption is the passive uptake of heavy metals by living or dead biomass via processes such as ion exchange, complexation, adsorption, and precipitation. Non-living biomass is often preferred for industrial use due to stability, low cost, and absence of nutrient requirements. |
| Effective biosorbents | Bacteria (Bacillus, Pseudomonas, Micrococcus), fungi (Aspergillus, Rhizopus, Penicillium), yeast (Saccharomyces, Candida), and algae (Sargassum, Spirogyra) demonstrated strong binding capacity. Agricultural and industrial wastes (e.g., rice straw, fermentation residues, tea waste) were also promising. |
| Operational parameters | Biosorption efficiency strongly depends on pH (optimal 4–6 for many metals), biomass concentration, surface chemistry, and metal ion concentration. Temperature influenced uptake less than other variables. |
| Capacity and selectivity | Uptake ranged from trace removal to >90% for certain metals, with some biosorbents showing high specificity (e.g., brown algae for cadmium, fungi for lead). Many biosorbents achieved reductions to below permissible discharge limits. |
| Economic feasibility | Biosorption offers low-cost, high-efficiency treatment and minimizes secondary sludge generation. Regeneration and recovery of metals from biosorbents add further value. |
| Mechanistic insights | Functional groups such as carboxyl, amine, hydroxyl, phosphate, and sulfhydryl groups were central in binding metals. Pretreatments (alkali, acid, heat) enhanced biosorption capacity in many systems. |
Key implications
For regulatory frameworks such as HTMC, biosorption offers a cost-effective method to ensure compliance with stricter heavy metal discharge limits. Certification requirements should include validation of biosorbent-based treatments as alternatives to conventional methods, especially where effluent concentrations are low but persistent. Industry applications are wide-ranging, from electroplating to mining waste remediation, with the added benefit of potential metal recovery. Research gaps remain in scaling from laboratory to industrial deployment and in standardizing operational protocols for biosorbent regeneration. Practical recommendations emphasize integrating biosorption into multi-barrier treatment systems and formally recognizing biosorbent technologies within certification criteria.
Citation
Abbas SH, Ismail IM, Mostafa TM, Sulaymon AH. Biosorption of heavy metals: A review.Journal of Chemical Science and Technology. 2014;3(4):74-102.
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
