Nina Ricci Palma Nicomel
I obtained my Bachelor’s degree in Agricultural Engineering from the University of the Philippines. Having taken some environmental science and sustainability courses in this program, I became interested in environmental issues, particularly those related to water pollution and remediation. This interest led me to obtain my Master’s degree in Environmental Sanitation from Ghent University in Belgium, where I worked with the removal of arsenic species from water using engineered nanoparticles encapsulated by novel classes of porous materials. This research made me aim to explore more about adsorption and desorption processes, specifically their application in the recovery of metals from wastes.
The increasing demand for metals marked the tremendous growth of metal extraction and refining operations worldwide. This growth resulted in the discharge of large volumes of wastes containing significant amounts of metals that can still be recovered. Applying the conventional metal recovery processes to wastes, practical applications are limited by certain factors, such as economics, production of atmospheric pollutants, and loss of metals during combustion. These limitations led to the development of alternative metal recovery processes, which include bioleaching and biosorption. Most bio-based processes, however, are still at the lab scale. Therefore, more studies are needed to design and optimize these bio-based processes, focusing on alternative applications, such as selective recovery of valuable metals and exploration of hybrid technologies. To do this, the development of a high throughput experimentation platform would be very advantageous. Thus, this research aims to set up and optimize a high throughput experimentation platform for biosorption and bioleaching of metals; and to apply this platform for selective recovery of technology-critical elements from industrial wastewaters and valuable metals from mine tailings.
Status PhD
- Supervisors / promoters : Gijs Du Laing, Tom Hennebel
- Final title of the PhD thesis : Development and application of a biosorption screening framework for selective metal removal and recovery from multicomponent aqueous streams
- Place and date of PhD defense (anticipated date if not yet defended): Gent, 29/03/2022
- PhD degree awarding institutions: Ghent University
Publications arising from the PhD
- Nicomel, N.R., Li, L.Y., Du Laing, G. (2022). Biosolids-based activated carbon for enhanced copper removal from citric-acid-rich aqueous media. Environmental Science and Pollution Research, 29, 74742-74755. https://doi.org/10.1007/s11356-022-21020-4
- Nicomel, N.R., Otero-Gonzalez, L., Williamson, A., Ok, Y.S., Van der Voort, P., Hennebel, T., Du Laing, G. (2022). Selective copper recovery from ammoniacal waste streams using a systematic biosorption process. Chemosphere, 286, 131935. https://doi.org/10.1016/j.chemosphere.2021.131935
- Nicomel, N.R., Otero-Gonzalez, L., Folens, K., Mees, B., Hennebel, T., Du Laing, G. (2021). Selective and enhanced nickel adsorption from sulfate- and calcium-rich solutions using chitosan. Separation and Purification Technology, 276, 119283. https://doi.org/10.1016/j.seppur.2021.119283
- Nicomel, N.R., Otero-Gonzalez, L., Arashiro, L., Garfi, M., Ferrer, I., Van Der Voort, P., Verbeken, K., Hennebel, T., Du Laing, G. (2020). Microalgae: a sustainable adsorbent with high potential for upconcentration of indium(iii) from liquid process and waste streams. Green Chemistry, 22, 1985-1995. https://doi.org/10.1039/C9GC03073E
Link to PhD thesis
https://biblio.ugent.be/publication/8746624Short abstract/summary
To meet the global challenges of sustainable metal supply, a new approach to metal recovery must be established. Metal-bearing liquid streams from different industrial processes have been recently viewed as potential secondary metal resources, complementing the unsustainable primary metal production. Metal recycling from these resources not only conserves the limited natural resources but also controls waste generation resulting in harmful waste discharges to different environmental matrices. However, metal recycling rates are still too low or non-existent for many metals despite this alarming environmental issue. Biosorption is a potential metal recovery technology for metal-bearing liquid streams, known for its cost-effectiveness, high efficiency, simple operation, and low waste generation. Researchers have widely investigated metal biosorption in the past; however, this technology still lacks industrial applications because most biosorption studies do not contribute to a better understanding of the entire process. The problem is not with the potential of the technology but the lack of a systematic approach to identify and apply the most efficient biosorbent and testing conditions to any given liquid stream. A systematic approach to biosorption studies can simultaneously evaluate biosorbents with different surface properties for their adsorption capacities in a multicomponent liquid stream with known water chemistry conditions. With this systematic evaluation, more accurate results are obtained since all essential factors affecting the biosorption process (i.e., liquid stream components and characteristics, metal speciation, and biosorbents characterizations) are considered and interrelated to underpin the selection of the most optimal biosorbent for the studied liquid stream. Metal speciation, in particular, is a valuable tool in understanding the biosorption processes but is often overlooked by many researchers. Given the multicomponent nature of target liquid streams, where metals and complexing agents co-exist, metal complexation could affect metal speciation and adsorption and, therefore, should be exploited to improve removal efficiencies and selectivity. Thus, researchers should direct biosorption to new routes, including the systematic evaluation of the existing inventory of biosorbents for selective metal recovery. This Ph.D. thesis provides an overview of the previously conducted metal biosorption studies in the presence of complexing agents and proposes a new approach to metal biosorption to address existing research gaps.
Chapter 1 presents the background, motivation, and objectives of the study. This chapter introduces the problems associated with the intensified demand for metals in many industrial applications. These problems include the limited metal reserves available and the energy-intensive primary metal production that highly impacts the environment. For these reasons, secondary metal resources in the form of metalbearing liquid streams should be considered. Biosorption was introduced as a potential metal recovery technology for these secondary metal resources but should be improved by considering multicomponent solutions representative of real liquid stream conditions and linking all the important factors affecting the biosorption process to identify the optimal biosorbent for a particular liquid stream. Thus, the goals of this study are to (i) develop a biosorption screening framework that considers real multicomponent liquid streams and integrates chemical speciation modeling and biosorbent characterizations in finding an efficient and selective biosorbent for the studied liquid stream; (ii) apply the biosorption screening framework to different case studies, mostly involving real (bio)leachates; and (iii) evaluate the potential of biosorption in a column setup. Since real secondary metal resources are mostly multicomponent in nature, where the target metal co-exists with other metals and complexing agents, the influence of metal complexation on metal adsorption should be investigated. Chapter 2 presents a review of metal (bio)sorption studies in the presence of complexing agents. This chapter emphasized that the effects of complexing agents on metal biosorption and the extent of these effects largely depend on the components of the aqueous stream and the conditions (e.g., pH, concentration) at which these components are present. Opposite to the notion that complexation mainly inhibits metal (bio)sorption, complexation also often causes enhancement or invariance of metal (bio)sorption. Several factors influence the effects of complexing agents; however, it was generalized that the ability of metal complexes to be adsorbed on the (bio)sorbent surface is the principal factor. Chemical speciation modeling is an essential tool for assessing and optimizing this interaction. Finally, this chapter found that most of the reviewed metal complexes adsorption studies generally involved non-biobased sorbents, specifically synthesized adsorbents, which do not always guarantee the enhancement of metal adsorption. Considering these insights, a systematic evaluation with a holistic approach dealing with all factors that affect the biosorption process was introduced in Chapter 3. This framework could identify better and more selective biosorbents for future metal recovery from secondary metal resources, such as leachates and wastewaters, by highlighting the importance of the target liquid stream characteristics, integrating chemical speciation modeling and biosorbent characterizations, and investigating the interaction between the target metal and other liquid stream components to address selectivity. This Ph.D. thesis covered four biosorption studies. The first one focused on microalgal biomass as In(III) biosorbent for secondary resources, such as leachates from sludge produced by zinc processing industries (e.g., jarosite) and wastewater from indium tin oxide etching processes (Chapter 4). The effects of pH, contact time, initial metal concentration, presence of competing ions, and desorption on In(III) biosorption by microalgal biomass were investigated in batch experiments. The estimated maximum adsorption capacity (qmax) of microalgae for In(III) was 0.14 mmol/g, higher than those of chemically modified adsorbents reported in the literature. This biosorbent was found selective for In(III) over other metals, such as Cu(II), Zn(II), and Al(III), but not Fe(III), which highlights the importance of studying multicomponent solutions for accurate assessment of the adsorption performance of a biosorbent. For recovery purposes, the study has shown that 0.1 M HCl could effectively desorb in (III) ions adsorbed on microalgal biomass; however, burning the In-loaded biosorbent to obtain In-rich ash could be a better option to recover In(III). The biosorption screening framework was first applied in Chapter 5, which dealt with Cu(II) biosorption from ammoniacal solutions. This approach has identified the optimal biosorbent—pinecone—to remove Cu(II) from real Cu–NH3 leachates. Despite 2 M NH3 and 5 mM Zn(II) present, pinecone achieved a high Cu(II) qmax of 1.1 mmol/g. The results also suggested that pinecone works over a wide pH range (pH 5-12), which is relevant for treating actual (NH4)2CO3 rich effluents. Furthermore, the presence of Zn(II) can improve the qmax of pinecone for Cu(II) from NH3-rich streams. Biosorption using pinecone offers a sustainable approach to treat Cu–NH3 liquid streams and a new route to recycle Cu for potential use in the metallurgical industries. In the same way, Chapter 6 evaluated biosolids-derived materials for the adsorption of Cu(II)–citric acid complexes, which are commonly present in wastewaters discharged by electroplating industries. Among the tested adsorbents, only the biosolids-based activated carbon (SBAC) displayed enhanced Cu(II) removal from 64.0% to 93.5% of the initial 1 mM Cu(II) when 100 mM citric acid was present. The increased qmax from 0.14 mmol/g to 0.30 mmol/g further confirmed this positive effect of citric acid on Cu(II) adsorption onto SBAC. Furthermore, SBAC could decrease the residual Cu(II) in the solution to below the discharge limit of 0.05 mM for metal finishing point sources in 1 h through a sequential adsorption setup. This study proved that the production of activated carbon from waste biosolids could be a sustainable way to manage the continuous generation of biowastes while simultaneously producing an effective adsorbent for removing Cu(II) from citric acid-rich liquid streams. Chapter 7 explored the potential of chitosan for Ni(II) adsorption from sulphate and Ca(II)- rich liquid streams. Using a real Ni(II)/Ca(II)/sulphate bearing leachate, chitosan was proven to be a selective Ni(II) biosorbent. Sulphate had a positive effect on Ni(II) adsorption, while Ca(II) did not have any effect. Chitosan achieved an estimated qmax of 1.43 mmol/g even with 500 mM sulphate and 10 mM Ca(II) present. Chemical speciation modeling and chitosan characterizations confirmed that the formation of NiSO40 species contributed to the enhanced Ni(II) adsorption onto chitosan. Furthermore, chitosan was selective for Ni(II) over Ca(II) and Cr(III) as validated in a column setup using real leachate. This study has demonstrated the potential of chitosan for Ni(II) adsorption from sulphate and Ca(II)-rich streams without the need for pre-adsorption treatments that complex liquid streams usually require. Chapter 8 presents the conclusions and research recommendations of this thesis. This chapter also detailed the limitations of biosorption as a metal recovery technology. Overall, the results of this research have shown that the advantages of biosorption are becoming more evident, especially with the increasing environmental awareness of the scientific and engineering community, policymakers, and general public, making it more competitive than the technologies already being used at full scale for metal removal and recovery.
