Publications
177 results found
Gómez M, Grimes S, Yang L, et al., 2023, Novel resource-efficient recovery of high purity indium products: unlocking value from end-of-life mobile phone liquid crystal display screens, Journal of Environmental Chemical Engineering, Vol: 11, ISSN: 2213-3437
Liquid crystal display (LCD) screens found in most electrical and electronic equipment consume approximately 75% of the total indium produced globally. Due to indium’s unique properties and applications, the escalation in demand for the metal and the threat to supply of the metal, mined primarily as a by-product of zinc production, are critical. To mitigate these challenges the need to recover indium from end-of-life (EoL) products is becoming an imperative. In this work, EoL mobile phones (EoL-MPs), which represent a resource-rich stream for critical metals in general, and, specifically indium from LCDs, are used as a feedstock. Using a simulated Model Test System, with the task-specific ionic liquid, Cyphos 101, the optimal conditions for recovery of indium are determined before application to real samples. A complete hydrometallurgical process was developed for the recovery of indium from as-received EoL-MP LCDs as a four-step process involving pre-treatment, liquid-liquid extraction, elution and reduction, using the task-specific IL, Cyphos 101, as extractant. This novel hydrometallurgical process developed can achieve overall efficiencies of ≥ 90% for indium recovery in the form of two high-purity (≥ 99%) indium products of commercial value and offers a promising approach for recovery from any e-waste stream rich in indium. Moreover, this low energy process permits the reuse of the IL up to five consecutive times and has the potential to unlock value as polymeric films, glass substrate and liquid crystal for recycle and reuse within the circular economy.
Gómez M, Grimes S, Bin-Jamaludin D, et al., 2023, Novel closed-loop recovery of light rare earth elements, as their oxides, from end-of-life mobile phone speakers using [Hbet][Tf2N], Journal of Environmental Chemical Engineering, Vol: 11, ISSN: 2213-3437
The use of rare earth elements (REEs) in many applications has proliferated in recent years. Growing demand for these elements, driven by global economic growth, a shift towards green technologies and the monopoly of their production by China, has led to their instability and shortage. The drive to source REEs from alternative secondary sources is imperative. Here, End-of-Life Mobile Phones (EoL-MPs), which represent a resource-rich stream for critical metals in general, and, specifically REEs, are used as feedstock. Exploiting the thermomorphic properties of the IL system, [Hbet][Tf2N]:H2O, the effects of time, water content and temperature for optimal leaching are determined in binary (Nd2O3-Pr2O3) and ternary (Nd2O3-Pr2O3-Fe2O3) systems, with the IL showing strong selectivity for oxides of light REEs. A complete hydrometallurgical process for the recovery of REEs, as oxides, from as-received EoL-MP speakers is developed involving pre-treatment, leaching, precipitation, and calcination, using the IL, [Hbet][Tf2N], as leaching agent. Each step was optimised to convert embedded REEs into their oxides to permit their full recovery. This novel closed-loop recycling process offers high selectivity for light REEs, utilising mild conditions, permitting the reuse of the IL up to five cycles, generating little waste and recovering the light REEs (Nd and Pr) with ≥ 90% efficiency and purity of product of ≥ 98%. Moreover, other highly valuable heavy REEs (Dy and Tb) are retained in the residue offering potential for their recovery. The proposed process provides a sustainable and efficient approach to close the gap between their supply and demand for these critical materials.
Gomez M, Grimes S, Fowler G, 2023, Novel hydrometallurgical process for the recovery of copper from end-of-life mobile phone printed circuit boards using ionic liquids, Journal of Cleaner Production, Vol: 420, ISSN: 0959-6526
Printed circuit boards, which are embedded in mobile phones, are complex composite materials containing valuable components of strategic and critical importance. With the number of mobile phone devices operating worldwide expected to reach 18bn by 2025, their low recycling rate leads to high tonnages of waste printed circuit boards (WPCBs) at their end of life. Copper, representing 58% of the total metal content in an end-of-life mobile phone (EoL-MP) and the main metal present in the printed circuit board, with an average of 27.8 wt %, offers a resource-rich source of this strategic metal for recovery. To overcome the limitations associated with conventional technologies for recycling WPCBs, use of greener technologies (ionic liquids (ILs) as leaching agents), offers greater potential for the recovery of copper from this waste stream. Presented here for the first time is an optimised hydrometallurgical process for recovery of copper involving pre-treatment, leaching, and electrowinning and the use of two task-specific ionic liquids. The pre-treatment step, using the IL [Bmim]BF4 proved to be a clean, efficient, and non-polluting system for the separation of solder and electronic components (ECs) from WPCBs, at 210 °C, 150 rpm for 15 min, favouring the enrichment of copper for a subsequent recovery process. The IL, [Bmim]HSO4, successfully leaches >99% of copper from pretreated WPCBs under the optimal conditions of 30 %v/v [Bmim]HSO4, 10 %v/v H2O2, and 60 %v/v H2O at 60 °C, 1:15 solid to liquid ratio for 2 h. Recovery of copper is achieved through direct electrowinning from the [Bmim]HSO4-leach solution, as electrolyte. Under controlled deposition conditions of 100 mA (4.2 V) during 2 h, 100% of copper (>99% purity) is recovered with an average current efficiency of 78% and an energy consumption of 4.5 kWh/kg Cu. This work combines a dual leaching and electrowinning system that is clean, environmentally friendly, minimises reagent use and spent wastes
Gómez M, Grimes S, Qian Y, et al., 2023, Critical and strategic metals in mobile phones: a detailed characterisation of multigenerational waste mobile phones and the economic drivers for recovery of metal value, Journal of Cleaner Production, Vol: 419, ISSN: 0959-6526
Mobile phones have a high embedded value of interest within a circular economy. With the number of these devices operating worldwide expected to reach 18bn by 2025 their low recycling rate leads to large tonnages of End-of-Life Mobile Phones (EoL-MPs) and de facto a challenging waste stream. The rapid replacement of mobile phones to meet consumer demand further compounds the challenges due to increased demand for raw materials, increased energy, and water consumption, and, where uncontrolled and poor disposal at end-of-life occurs, significant impacts on health and the environment.EoL-MPs comprise a complex and heterogeneous combination of materials that include strategically and economically important high technology metals, many of which are classified as critical by the EU. A detailed characterisation of key components (PCBs, casings, screens, cameras, and speakers) of multigenerational (feature phones, multimedia phones, and smartphones) EoL-MPs is studied to determine the potential for recovery of both metal and non-metallic fractions and the economic drivers for recovery of the metal value. On average, the major mass fraction distributed in a mobile phone is: plastics (40%), metals (35%) and ceramics (25%).The results show that 1 tonne of EoL-MPs can contain up to 53 Kg copper, 141 g gold, 270 g silver, 10 g platinum, 18 g palladium and 3.3 Kg rare earth elements, among other valuable metals, with many of these elements found to be at least twice, and in some cases, up to 600 times more concentrated than in their natural ores. The calculated economic value of the EoL-MPs components is in the order: cameras (86,860 US$/ton), printed circuit boards (55,459 US$/ton), speakers (21,853 US$/ton) and screens (3,779 US$/ton). Based on the predicted 5 billion EoL-MPs discarded by the end of 2022, this waste stream has a potential economic value of US$ 9.25 billion. Use of EoL-MPs as a secondary resource-rich stream of these critical materials therefore offers a route t
Velis CA, Wilson DC, Gavish Y, et al., 2023, Socio-economic development drives solid waste management performance in cities: a global analysis using machine learning, Science of the Total Environment, Vol: 872, ISSN: 0048-9697
Mismanaged municipal solid waste (MSW), the major source of plastics pollution and a key contributor to climate forcing, in Global South cities poses public health and environmental problems. This study analyses the first consistent and quality assured dataset available for cities distributed worldwide, featuring a comprehensive set of solid waste management performance indicators (Wasteaware Cities Benchmark Indicators – WABI). Machine learning (multivariate random forest) and univariate non-linear regression are applied, identifying best-fit converging models for a broad range of explanatory socioeconomic variables. These proxies describe in a variety of ways generic levels of progress, such as Gross Domestic Product – Purchasing Power per capita, Social Progress Index (SPI) and Corruption Perceptions Index. Specifically, the research tests and quantitatively confirms a long-standing, yet unverified, hypothesis: that variability in cities' performance on MSW can be accounted for by socioeconomic development indices. The results provide a baseline for measuring progress as cities report MSW performance for the sustainable development goal SDG11.6.1 indicator: median rates of controlled recovery and disposal are approximately at 45 % for cities in low-income countries, 75 % in lower-middle, and 100 % for both upper-middle and high-income. Casting light on aspects beyond the SDG metric, on the quality of MSW-related services, show that improvements in service quality often lag improvements in service coverage. Overall, the findings suggest that progress in collection coverage, and controlled recovery and disposal has already taken place in low- and middle-income cities. However, if cities aspire to perform better on MSW management than would have been anticipated by the average socioeconomic development in their country, they should identify ways to overcome systemic underlying failures associated with that socioeconomic level. Most alarmingly, ‘bus
Bruch J-R, Bokelmann K, Grimes SM, 2022, Process development options for electronic waste fractionation to achieve maximum material value recovery, Waste Management and Research, Vol: 40, Pages: 54-65, ISSN: 0734-242X
Revised legislation and bans on imports of waste electrical and electronic equipment (WEEE) into many Asian countries for treatment are driving the need for more efficient WEEE fractionation in Europe by expanding the capacity of treatment plants and improving the percentage recovery of materials of economic value. Data from a key stakeholder survey and consultation are combined with the results of a detailed literature survey to provide weighted matrix input into multi-criteria decision analysis calculations to carry out the following tasks: (a) assess the relative importance of 12 process options against the 6 industry-derived in-process economic potential criteria, that is, increase in product quality, increase in recycling rate, increase in process capacity, decrease in labour costs, decrease in energy costs and decrease in disposal costs; and (b) rank 25 key technologies that have been selected as being the most likely to benefit the efficient sorting of WEEE. The results indicate that the first stage in the development of any total system to achieve maximum economic recovery of materials from WEEE has to be the selection and application of appropriate fractionation process technologies to concentrate valuable components such as critical metals into the smallest possible fractions to achieve their recovery while minimising the disposal costs of low-value products. The stakeholder-based study has determined the priority for viable technical process developments for efficient WEEE fractionation and highlighted the economic and technical improvements that have to be made in the treatment of WEEE.
Grimes SM, Maguire D, 2020, Assessment of priorities in critical material recovery from waste electrical and electronic equipment, Resources Policy, Vol: 68, Pages: 1-10, ISSN: 0301-4207
A major problem in developing environmental management systems for assessing recovery priorities for high added-value materials such as critical metals from wastes is that the input data required are contained in a variety of databases compiled for different purposes with different levels of content and accuracy. To deal with decision-making priorities for environmental issues where uncertainties and inconsistencies are inherent in input data sources a Multi-Criteria Decision Analysis (MCDA) approach using an Analytic Hierarchy Process (AHP) to determine weights and fuzzy numbers to account for input data uncertainties is developed and is illustrated for determination of critical metal recovery priorities from Waste Electrical and Electronic Equipment (WEEE) in Europe. A spreadsheet programme with many user-friendly input and output features is developed to aid data-handling and the calculations required in the MCDA approach. Where data uncertainties exist, weighted input parameters for the critical metals are determined by an absolute judgement panel of key stakeholders and include data on: recovery potential, geographical supply concentration and stability, end use substitution, future metal demand and economic importance in key industrial sectors. Sensitivity analyses can be carried out on results of recovery priority outputs by simple numerical variation of input parameters and/or by the use of specialist input decision panels representing stakeholder groups with differing priorities, and the results suggest that recovery priorities in the European situation should concentrate on gallium, indium and germanium. The spreadsheet-MCDA program set up in developing the methodology for criticality has wide general application in environmental decision-making analysis particularly where uncertainties exist in the input data required.
Donaldson JD, Grimes SM, Mehta L, et al., 2019, Application of thermal desorption to the development of a gas chromatographic/mass spectrometric method for the determination of toluene, chlorinated aromatic hydrocarbons, and 2,3,7,8-tetrachlorodibenzo-<i>p</i>-dioxin in combustion emissions, JOURNAL OF AOAC INTERNATIONAL, Vol: 86, Pages: 39-43, ISSN: 1060-3271
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- Citations: 11
Grimes SM, Ciuffa F, Cooper J, et al., 2018, Development of a vacuum-packing system for food waste from urban catering facilities, Proceedings of the Institution of Civil Engineers. Waste and Resource Management., Vol: 171, Pages: 114-120, ISSN: 1747-6526
A novel vacuum-packing system is developed for food waste storage and collection under the conditions found in high-density urban and metropolitan catering establishments that has the following beneficial outcomes: (a) a reduction of 38% in the volume of food waste to be stored for collection; (b) a reduction in the physical space required on-site for storage of multiple vacuum packs of waste; (c) containment of the food waste stored in sanitised conditions, thus maintaining the integrity of the waste and extending the useful life of the waste in terms of its ideal composition for optimum beneficial recovery by anaerobic digestion or in-vessel composting, and reducing problems due to odour and vermin; and (d) reduction in the number of vehicle movements required to transfer the wastes to treatment facilities and their environmental impacts, while also achieving savings of £13–16 per bin lift in London, along with a considerable reduction in overall cost.
Grimes SM, Kewcharoenwong P, 2017, Dual-functionality ionic liquid mix for extraction and esterification of fatty acids as a step towards increasing the efficiency of conversion of waste cooking oils to biodiesel, Journal of Chemical Technology and Biotechnology, Vol: 92, Pages: 2098-2105, ISSN: 0268-2575
BACKGROUND: The increasing value of pure vegetable oils has made the use of waste cooking oils an attractive alternative feedstock for biodiesel production but the presence of free fatty acids in the waste significantly reduces efficiency of the conversion.RESULTS: A low-temperature mixed ionic liquid system with dual extraction and catalytic functions for the conversion of waste oils containing high levels of free fatty acids to biodiesel was successfully trialled. The solvent, a totally miscible system of HPyrBr and the Brønsted acid, SPyrHSO4, allows the key properties of each ionic liquid, as extractant or catalyst, to work uninhibited by the presence of the other. Extraction of free fatty acids from vegetable oils and their conversion to methyl esters in high yield is demonstrated for vegetable oils, containing single and mixed fatty acids, and for a model waste cooking oil. The oil separated from free fatty acids in the waste has a low acid value and can be converted efficiently to biodiesel; with the ionic liquid solvent recovered unchanged for reuse.CONCLUSIONS: A mixed ionic liquid extraction-esterification solvent process has been developed to effect efficient conversion of free fatty acids in waste vegetable oils to biodiesel and their conversion to esters.
Wang W, Ma X, Grimes S, et al., 2017, Study on the absorbability, regeneration characteristics and thermal stability of ionic liquids for VOCs removal, Chemical Engineering Journal, Vol: 328, Pages: 353-353, ISSN: 1385-8947
A novel method of removal of volatile organic compounds (VOCs) using the ionic liquid [Bmim][NTf2] as an absorbent is developed as a contribution to dealing with recent severe smog incidents in China. The effects of concentration, temperature and flow rates on the ability of [Bmim][NTf2] to absorb VOCs were studied using toluene as a model volatile organic pollutant. The potential of the use of [Bmim][NTf2] as an absorbent for VOCs is shown by the solubility of toluene in the ionic liquid; the absorptivity of the ionic liquid for toluene; and the fact that absorbed toluene can be removed easily from [Bmim][NTf2], permitting recycle of the ionic liquid in multiple reuse phases. The solubility of toluene in [Bmim][NTf2] is 61.5% at 20 °C and atmospheric pressure; the highest absorptivity of [Bmim][NTf2] for toluene is 98.3%, achieved at a toluene concentration of 300 ppm and a flow rate of 50 mL min−1 at 20 °C; and the absorptivity of the ionic liquid is >94% over a wide range of conditions. The ionic liquid can be recovered and recycled in the absorption process at least five times, reducing the reagent cost in the VOC removal process.
Wang W, Fu L, Sun J, et al., 2017, Experimental Study of Microwave-Induced Discharge and Mechanism Analysis Based on Spectrum Acquisition, IEEE Transactions on Plasma Science, Vol: 45, Pages: 2235-2242, ISSN: 0093-3813
When conductor or semiconductor materials areexposed to microwave radiation in different atmospheres (Ar, He,N2, and O2+N2) intense discharge phenomena are observed. Thedischarge phenomena, generated when strips of the metals Fe, Al,and Zn or particles of the semiconductor SiC are irradiated withmicrowaves, are characterized experimentally using spectrumacquisition and analysis. Filamentary discharge is observed inan Ar atmosphere while spark discharge is observed in He, N2,and O2+N2 atmospheres. The spectral lines of the dischargesare concentrated mainly in the visible region, but there are alsopeaks in the ultraviolet region. The nature of the discharge andthe specific details of the spectra are influenced by: 1) the targetmetal or semiconductor used; 2) the atmosphere; and 3) themicrowave field characteristics. The spectra always consist of twoparts: one corresponding to the target metal or semiconductorirradiated by the microwaves and the other due to the formationof the high-energy excitation states of atoms, molecules, andions induced in the gaseous atmosphere. The microwave-induceddischarge and the corresponding luminous and plasma effectshave potential uses as energy sources in many applicationsincluding chemical or photocatalytic enhancement of reactionsand the destruction of volatile organic compounds for whichpreliminary results are encouraging.
Schaeffer N, Feng X, Grimes SM, et al., 2017, Recovery of an yttrium europium oxide phosphor from waste fluorescent tubes using a Brønsted acidic ionic liquid, 1-methylimidazolium hydrogen sulfate, Journal of chemical technology and biotechnology, Vol: 92, Pages: 2731-2738, ISSN: 0142-0356
BACKGROUNDSpent fluorescent lamps, classified as hazardous waste in the EU, are segregated at source. Processes for the recovery of critical rare-earth (RE) elements from the phosphor powder waste, however, often involve use of aggressive acid or alkali digestion, multi-stage separation procedures, and production of large aqueous waste streams which require further treatment.RESULTSTo overcome these difficulties phosphor powder pre-treated with dilute HCl was leached with a 1:1 wt. [Hmim][HSO4]:H2O solution at a solid:liquid ratio of 5%, at 80 °C for 4 h with stirring at 300 rpm to recover 91.6 wt% of the Y and 97.7 wt% of the Eu present. The yttrium-europium oxide (YOX), (Y0.95Eu0.05)2O3, recovered by precipitating the dissolved RE elements from the leach solution with oxalic acid and converting the oxalate to an oxide phase by heating, was characterised by FTIR, XRD and luminescence analysis. The analyses suggest the recovered oxide has the potential to be directly reused as YOX phosphor. Regeneration and reuse of the ionic liquid is achieved with only minor leaching efficiency losses found over four leaching/recovery cycles.CONCLUSIONThe recovery of yttrium europium oxide from waste fluorescent tube phosphor by a simple efficient low cost ionic liquid process has been developed.
Grimes SM, Yasri NG, Chaudhary AJ, 2017, Recovery of critical metals from dilute leach solutions - Separation of indium from tin and lead, Inorganica Chimica Acta, Vol: 461, Pages: 161-166, ISSN: 1873-3255
The strategic metal indium is recovered from solutions containing tin and lead that are typical of those obtained from leach solutions of metal component fractions of electronic waste including the leach solutions from indium tin oxide thin film conductive layers that contain only indium and tin. Almost total recovery of the metals can be achieved from nitric, perchloric and acetic acid leach solutions using a novel cylindrical mesh electrode electrolysis cell under appropriate conditions. The optimum separation of indium from tin and lead is achieved by a novel three-stage process from nitric acid media in the presence of SCN− as a complexing agent. Lead is removed from dilute indium-tin-lead solutions in the first stage from 0.1 mol L−1 nitric acid solution by electrodeposition over an 8 h period in the absence of SCN− to give a residual solution containing a maximum of 2 mg L−1 of lead (97% recovery). Tin is removed in the second stage by electrodeposition over an 8 h period from the solution after addition of 0.02 mol L−1 SCN− to give a maximum residual electrolyte tin concentration of 3 mg L−1 (94% recovery). In the third stage indium is recovered at the anode of the cylindrical mesh electrode cell as an oxy-hydroxide phase by increasing the SCN− concentration to 0.1 mol L−1 and carrying out the electrolysis for a period of 24 h to give a residual solution containing 1 mg L−1 of indium (98% recovery).
Schaeffer N, Grimes SM, Cheeseman CR, 2016, Use of extraction chromatography in the recycling of critical metals from thin film Leach solutions, Inorganica Chimica Acta, Vol: 457, Pages: 53-58, ISSN: 1873-3255
Phosphors and optoelectronic thin film electronic device layers contain critical metals including lanthanides and indium that should be recycled. Solvent impregnated resins (SIRs) containing (i) DEHPA (ii) DODGAA and (iii) DODGAA with the ionic liquid [C4mim][Tf2N] are investigated in extraction chromatography methodologies to recover and separate critical metals from dilute solutions that model those leached from thin films. Optimum adsorption of metals occurs at pH 1.5-3.5 but is highest on DODGAA-[C4mim][Tf2N]. The recovery and separation of adsorbed metal species on the DODGAA-[C4mim][Tf2N] SIR resin from solutions containing the glass matrix ions, Ca(II) and Al(III), along with In(III) and Sn(IV) or lanthanide ions is achieved by elution with HNO3. Ca(II) and Al(III) are completely eluted with 0.1M HNO3 retaining the target critical metal species on the resin. Separation of In from Sn is achieved by elution of In(III) with 2.5M HNO3 and Sn(IV) with 5M acid. La is separated from the other lanthanides by elution of La(III) with 2.5M HNO3 and the remaining lanthanides with 5M acid. The SIR resins can be reused over a series of at least five cycles of loading,stripping, and rinsing to reduce reagent costs and achieve economic critical metal recovery byextraction chromatography.
Grimes SM, Thompson F, 2016, Recovery of lubricant base oils using ionic liquid processes, Proceedings of Institution of Civil Engineers: Waste and Resource Management, Vol: 169, Pages: 73-82, ISSN: 1747-6526
Two novel low-temperature ionic liquid processes are developed for the recovery of base oils from waste lubricant oils. One uses 3-(triethoxysilyl)-propylammonium-3-(triethoxysilyl)-propyl carbamate (TESAC), in which the waste lubricant base oil is insoluble, and the other uses trihexyl(tetradecyl)phosphonium chloride (P6,6,6,14Cl) in which the base oil is soluble. In the 3-aminopropyl-triethoxysilane (TESA)/TESAC process, waste oil components, including the base oil, are dissolved in the solvent TESA which is converted, in situ, with carbon dioxide to TESAC, recovering the base oil as an insoluble layer. In the P6,6,6,14Cl process, the base oil is separated from most additives as a solution in the ionic liquid from which it can be extracted with methanol. The recovered oils from both processes have properties consistent with lubricant oils in commercial use and the ionic liquids can be recovered for recycle minimising reagent use and providing a route to closed-loop base oil recovery and recycle.
Schaeffer N, Grimes S, Cheeseman C, 2015, Interactions between trivalent rare earth oxides and mixed [Hbet][Tf2N]:H2O systems in the development of a one-step process for the separation of light from heavy rare earth elements, Inorganica Chimica Acta, Vol: 439, Pages: 55-60, ISSN: 1873-3255
The factors, including ionic liquid:water ratios, temperature, solvent:solute contact times, and the effect of dissolved rare earth metal ions on the [Hbet][Tf2N]:H2O thermometric phase change are determined to develop a process for separating the light from the heavy rare earth metal oxides in [Hbet][Tf2N]:H2O mixtures. The relative solubility data for three light (La2O3, Nd2O3, and Eu2O3), two heavy (Y2O3 and Yb2O3) rare earth metal oxides (REOs), and Gd2O3 at different temperatures and different solute:solvent contact times are reported for 1:1 [Hbet][Tf2N]:H2O. The light REOs dissolve easily at 57 °C with the La and Eu reaching maximum solubility within minutes while the heavy REOs have very low solubilities at this temperature with negligible amounts being dissolved for contact times less than 80 min. Gd2O3 dissolves more slowly than the La, Eu, and Nd oxides at 57 °C reaching maximum solubility only after 160 min. Changing the [Hbet][Tf2N]:H2O ratio from 1:1 to 16:1 increases the time required to dissolve the REOs. The times taken to reach maximum solubility decrease for all of the REOs up to 95 °C, resulting in the separations between the light and heavy rare earth elements, and Gd becoming less distinct. The presence of rare earth metal ions in [Hbet][Tf2N]:H2O results in a reduction in the upper critical solution temperature (UCST) of the solvent from 55.6 °C to as low as 31.8 °C with Gd3+. The best separation of light from heavy REOs is achieved at 57 °C but better separation of Gd from the light REOs is achieved at 40 °C, below the solvent UCST. The best conditions for a one-step separation of light from heavy REOs in [Hbet][Tf2N]:H2O mixtures is achieved with 1:1 [Hbet][Tf2N]:H2O at 57 °C using short contact oxide:solvent times (maximum 5 min). Separations of light from heavy REOs, in waste phosphor samples, containing La2O3, CeO2, Eu2O3, Gd2O3, Tb3O4 and Y2O3, are also achieved even in the presence of high concentrations
Bourtsalas A, Vandeperre L, Grimes S, et al., 2015, Properties of ceramics prepared using dry discharged waste to energy bottom ash dust, Waste Management & Research, Vol: 33, Pages: 794-804, ISSN: 1096-3669
Bourtsalas A, Vandeperre LJM, Grimes SM, et al., 2015, Production of pyroxene ceramics from the fine fraction of incinerator bottom ash, Waste Management, Vol: 45, Pages: 217-225, ISSN: 0956-053X
Incinerator bottom ash (IBA) is normally processed to extract metals and the coarse mineral fraction is used as secondary aggregate. This leaves significant quantities of fine material, typically less than 4mm, that is problematic as reuse options are limited. This work demonstrates that fine IBA can be mixed with glass and transformed by milling, calcining, pressing and sintering into high density ceramics. The addition of glass aids liquid phase sintering, milling increases sintering reactivity and calcining reduces volatile loss during firing. Calcining also changes the crystalline phases present from quartz (SiO2), calcite (CaCO3), gehlenite (Ca2Al2SiO7) and hematite (Fe2O3) to diopside (CaMgSi2O6), clinoenstatite (MgSiO3) and andradite (Ca3Fe2Si3O12). Calcined powders fired at 1080°C have high green density, low shrinkage (<7%) and produce dense (2.78g/cm3) ceramics that have negligible water absorption. The transformation of the problematic fraction of IBA into a raw material suitable for the manufacture of ceramic tiles for use in urban paving and other applications is demonstrated.
Grimes SM, Tanpoonkiat W, 2013, Thailand: Steps towards integrated solid waste management, Proceedings of Institution of Civil Engineers: Waste and Resource Management, Vol: 166, Pages: 167-176, ISSN: 1747-6526
The current waste management practices in Thailand have been analysed to identify changes that would be beneficial in achieving the criteria set by authorities for improvements in recycling and diversion from landfill to 2030. The numbers and combinations of selected treatment plants that would have to be introduced into Thailand to meet targets for diversion of biological waste from landfill and the production of energy over the planning period have been calculated for a number of scenarios. Sensitivity analyses are performed on the results obtained to account for changes in future assumptions on the amount of waste generated and the organic content of the residual waste. The methodology adopted in this work, to aid planning decisions on technology requirements into the future, was previously used to predict the treatment options for handling the organic fraction of waste generated in London. As a generic methodology, applied in this work to illustrate the types of results obtained from the analyses using specific sets of assumptions relevant to Thailand, it offers the capability and flexibility to take account of the effects on the outcome of any relevant scenarios that planners might wish to consider and any assumptions that they might wish to make.
Hussain Z, Grimes S, Shahid M, et al., 2013, Leaching of Copper Secondary Wastes: Possible Soil Contaminants, ASIAN JOURNAL OF CHEMISTRY, Vol: 25, Pages: 4051-4054, ISSN: 0970-7077
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Grimes SM, Lateef H, 2013, RECOVERY OF CHONDROITIN SULPHATE AND HYALURONIC ACID FROM SIMULATED SCALLOP GUT WASTE USING IONIC LIQUID METHODOLOGY, 13th International Conference on Environmental Science and Technology (CEST), Publisher: GLOBAL NEST, SECRETARIAT, ISSN: 1106-5516
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Lateef H, Gooding A, Grimes SM, 2012, Use of 1-hexyl-3-methylimidazolium bromideionic liquid in the recovery of lactic acidfrom wine, Journal of Chemical Technology and Biotechnology
BACKGROUND: Lactic acid has many different applications in a variety of industries including the food, cosmetics, packaging,leather and chemical industries. Current methodologies for lactic acid production are lengthy and complicated and moreefficient methods are being sought. Some organic wastes contain lactic acid and our work investigates the use of ionic liquids(ILs) in the efficient and selective extraction of lactic acid from organic waste using wine as a model system. The ionic liquidwaschosen based on its ability to selectively solvate and separate lactic acid from the remaining bulk waste material.RESULTS: Several ILs including 1-hexyl-3-methylimidazolium chloride (hmimCl), 1-hexyl-3-methylimidazolium bromide(hmimBr), 1-hexyl-3-methylimidazolium iodide (hmimI) and N-hexylpyridinium iodide (hpyrI) have been synthesized in highyield (68-95%) using microwave technology. Lactic acid is soluble in each of the ILs synthesized with optimum results achievedwith hmimBr where lactic acid is miscible in all proportions. HmimBr has been used to successfully separate and extract lacticacid from wine as confirmed by FTIR spectroscopy. Furthermore, it has been possible to recover the IL for recycle in subsequentextraction cycles where the efficiency for the extraction process increases with each recycle.CONCLUSION: HmimBr has been used for the first time in a novel process for the separation and recovery of lactic acid fromwine, as confirmed by FTIR spectroscopy. This work demonstrates a novel processwhich can be applied to the recovery of lacticacid from organic waste.
Abbe OE, Grimes SM, Fowler GD, 2011, Decision support for the management of oil well drill cuttings, Proceedings of Institution of Civil Engineers: Waste and Resource Management, Vol: 164, Pages: 213-220, ISSN: 1747-6526
Depending on the hole size and mud type used in the drilling process, oil well drill cuttings can be a relatively high-volume solid waste stream from drilling operations in the oil and gas exploration and production industry. Current management practices tend to involve thermal treatment followed by landfill disposal. The waste-to-resource conversion approach, however, provides opportunities that are not reflected in the current management system. The drill cuttings waste management decision support tool described in this work allows for the consideration of alternative reuse applications such as in construction materials, oil well reinjection, wetlands restoration, and the manufacture of stable leach-resistant material such as glass ceramics, in a move to divert treated drill cuttings from landfill towards zero waste disposal.
Cahill R, Grimes SM, Wilson DC, 2011, Extended producer responsibility for packaging wastes and WEEE - a comparison of implementation and the role of local authorities across Europe, WASTE MANAGEMENT & RESEARCH, Vol: 29, Pages: 455-479, ISSN: 0734-242X
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- Citations: 61
Grimes SM, Abbe OE, Fowler GD, 2011, Decision support for themanagement of oil well drillcuttings, Proceedings of the Institution of Civil Engineers. Waste and Resource Management., Vol: 164, Pages: 213-220
Depending on the hole size and mud type used in the drilling process, oil well drill cuttings can be a relativelyhigh-volume solid waste stream from drilling operations in the oil and gas exploration and production industry.Current management practices tend to involve thermal treatment followed by landfill disposal. The waste-to-resourceconversion approach, however, provides opportunities that are not reflected in the current management system. Thedrill cuttings waste management decision support tool described in this work allows for the consideration ofalternative reuse applications such as in construction materials, oil well reinjection, wetlands restoration, and themanufacture of stable leach-resistant material such as glass ceramics, in a move to divert treated drill cuttings fromlandfill towards zero waste disposal
Zglobisz N, Castillo-Castillo A, Grimes S, et al., 2010, Influence of UK energy policy on the deployment of anaerobic digestion, ENERGY POLICY, Vol: 38, Pages: 5988-5999, ISSN: 0301-4215
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- Citations: 23
Zglobisz N, Castillo-Castillo A, Grimes S, et al., 2010, Influence of UK energy policy on the deployment of anaerobic digestion, Energy Policy, Vol: 38, Pages: 5988-5999
Lateef H, Grimes S, Kewcharoenwong P, et al., 2009, Separation and recovery of cellulose and lignin using ionic liquids: a process for recovery from paper-based waste, JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY, Vol: 84, Pages: 1818-1827, ISSN: 0268-2575
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- Citations: 90
Bark M, Bland M, Grimes S, 2009, Report: Potential environmental impact of exempt site materials - a case study of bituminous road planings and waste soils, WASTE MANAGEMENT & RESEARCH, Vol: 27, Pages: 611-616, ISSN: 0734-242X
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