Perlite Today – Summer 2023

PERLITE TODAY PERLITE TODAY

September 17 – 20, 2023

Athens, Greece

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The Perlite Institute Annual Meeting is only open to current members. To refer a potential member, please direct them to our membership page HERE

HIGHLIGHTS OF MEETING TOPICS & SPEAKERS

In this newsletter, we chose to highlight a few of our speakers and tell you about their presentations. A complete schedule will be emailed to you soon.

Mortars and Plasters From Inorganic Materials With Improved Insulation Properties and Incorporation of CDWs

Achilleas Amanatidis, Principal Consultant, in.mat-Lab

As a founding member of e-CODOMH, in.mat-Lab participates in the development of new ecological mortars and plasters, which will show improved properties such as thermal insulation (thanks to the use of perlite composites), antibacterial properties (because of the use of nano-titania) while also incorporating recovered materials from CDWs. e-CODOMH Cluster was founded in 2021 with objectives for sustainable constructions, buildings and infrastructures in two priority axes: 1.) environmental sustainability with an emphasis on energy upgrading, and 2.) digitization of production.

Achilleas Amanatidis

Achilleas received his MSc in Mining & Metallurgy Engineering in 1992. After working eight years as a senior researcher in the NTUA/Lab of Metallurgy, he continued his professional career as Head of Refractories production at Mathios Refractories S.A. organizing and synchronizing operations of two plants and targeting the decrement of operational costs. In 2002, Achilleas entered the world of perlite as Technical Support Engineer for S&B Industrial Minerals S.A., responsible for international customers’ technical support, participating in various internal, B2B and EU funded R&D projects based on industrial minerals. He was also responsible for the knowledge database of a very wide range of perlite qualities from all around the world through lab and industrial tests and analyses. In 2010 and for the next six years, Achilleas took the position of Expanded Perlite Operations Manager with responsibilities over a multi-functional plant with everyday production, serving a range of perlite products covering construction, agriculture, hydroponics, filter aids, cryogenic insulation, fillers for paints and plastics. After S&B’s acquisition by Imerys, he joined Dr. Antonia Ekonomakou, in.mat-Lab’s founder, as Principal Consultant, bringing experience and a proven track record of success in the field of perlite, meeting the company’s goals and objectives for a professional consultancy to mining companies, perlite expansion plants and final producers.

Assessing the Environmental Performance of the Perlite Industry and Products

Professor Maria Taxiarchou, Associate Professor, Analysis and Design of Processes for Ores and Industrial Minerals, School of Mining & Metallurgical Engineering, National Technical University of Athens

In an era marked by increasing environmental concerns and a growing awareness of the impact of human activities on our planet, the need for sustainable practices in the industry has become paramount. In the same context, in the global marketplace, consumers are becoming increasingly environmentally conscious. This presentation will review how the perlite industry can quantify and communicate the environmental performance of their processes and products to customers, using Life Cycle Analysis (LCA) and Environmental Product Declaration (EPD).

Professor Maria Taxiarchou

Professor Maria Taxiarchou is a Mining and Metallurgical Engineer. She is currently an associate full-time professor in the School of Mining and Metallurgical Engineering, and she is a member of NTUA Research Committee, which is responsible for the management of all the research funds of the National Technical University of Athens. Her current activities involve research on technology development for the processing of ores and industrial minerals; development of energy efficient processes; design and techno-economic evaluation of new production processes; development of high-added value products from ores and industrial minerals for the construction and chemical industry; assessment of the environmental impact and LCA of products and processes. She has authored or co-authored 80 research papers and she has been granted one national and two international patents. She is a regular reviewer of several international journals in the field of metallurgical engineering, and she has participated in more than 65 European funded research projects. Currently, she is the executive director of the NTUA spin-off company, Lightcoce.

Future Perlite Sustainable Building Applications

Kostas Mitsios, Technical Director, Gulf Perlite LLC

During this session, Kostas will present the latest innovations for future perlite sustainable building applications. These applications promise a sustainable, global potential and provide strong showcases for the future of perlite in the construction industry.

Gulf Perlite LLC’s Application of Perlite Loose-Fill Wall Insulation at the First 3D Concrete Villa of Dubai 3D Concrete is the future in construction, and this full 3D building was built by a robotic machine in a short time (1 month/villa). It is sustainable (less emissions), safe (less accidents) and economical (less material wastage). Perlite loose-fill insulation is sustainable, ever-lasting, fire-resistant, time and cost-effective for the specific application. Within 20 years, 50% of the villas construction in the UAE will be 3D printed.

Assessment of Perlite Lightweight Concrete T Beams CFRP Strengthened and Anchored With U-Wraps

Following the construction market demand for structural lightweight concrete worldwide, Gulf Perlite LLC sponsored and participated together with the American University of Dubai in the first research paper for the use of Perlite lightweight concrete as a structural concrete. This is the first scientific study aiming to introduce medium density perlite lightweight concrete with compressive strength of min. 20 MPa (2,900 psi) for structural concrete applications (beams/ columns/slabs). Perlite lightweight concrete performance was tested to be similar to ordinary structural concrete, and it additionally offers the significant advantage of lightweight, reducing the structure weight/ load by 25%. It also acheives more flexibility in the structural design and provides significant cost-savings in construction.

Kostas Mitsios

For the last 12 years, Kostas Mitsios has been the Technical Director of Gulf Perlite LLC, a prominent Dubai-based perlite manufacturer and provider of perlite-based solutions for the construction, oil and gas, and horticultural sectors. Kostas holds bachelor’s and master’s degrees in civil engineering/ structural engineering and a M.Sc. degree in mining engineering from the esteemed National Technical University of Athens. Over the course of his 25-year career, he has garnered invaluable expertise in project management, serving as a Project Director at numerous residential and commercial high-end projects in Europe, with a particular focus on innovative building materials and methods, sustainability, cost, time and quality control; and fostering efficient and creative thinking. In his current role, Kostas devotes his efforts to advancing perlite and perlite lightweight concrete applications, delivering sustainable thermal insulation to the GCC buildings; and to providing innovative building solutions tailored to each project technical requirements and the extreme local climate conditions.

Lean Manufacturing – Perspective for the Perlite Industry

Chuck Vogelsang, Technical and Operations Consultant, Perlite Institute

Lean manufacturing is an operational approach to improve profits by streamlining processes and maximizing productivity to eliminate waste and maximize productivity. It is a methodology on how to continually improve the various processes involved in producing a product. During this session, find out how lean manufacturing saves time and money and improves customer satisfaction.

Chuck Vogelsang

Chuck Vogelsang has over 40 years of operational and technical background working with a variety of plants throughout the world to make improvements—improvements in both processes and costs. From a perlite industry standpoint, he has been in more than 100 perlite expansion plants and 10 ore mills and mines. He has been extensively involved with systems that make horticulture, construction, insulation, filter aid and filler type expanded grades.

Chuck has been involved with many products that were devoted to the needs of the customers and how to change or make a product for a specific application. He believes that the ultimate judge is the customer who votes on the acceptability and value of material with their money.

Message from the President

by Jake Hess

2023 ANNUAL MEETING HOTEL INFORMATION

Divani Apollon Palace & Thalasso

10 Agiou Nikolaou Str.

166 71 Vouliagmeni

Athens, Greece

The Perlite Institute Annual Meeting will take place at the Divani Apollon Palace & Thalasso in Athens Riviera, Greece. The block of rooms held for the meeting has been booked in full by members who have already confirmed their reservations for accommodation at the hotel.

For those that wish to participate in our Annual Meeting, but still haven't made your accommodations, we strongly suggest that you contact ALICE TRAVEL in Athens, the Official Travel Agent of the Perlite Institute Annual Meeting. There are just a few rooms still available at the hotel where the Annual Meeting will take place and they will be offered to you on a firstcome, first-served basis. If these few rooms are also booked, ALICE TRAVEL will provide you alternatives in nearby hotels that are the same standards as the Annual Meeting hotel. You can contact ALICE TRAVEL as follows:

Mr. Dimitris Economou, Sales Director dimitris@alicetravel.gr, tel. +30 6974 071894

Please make sure you book your accommodations on time, as our Annual Meeting takes place in a rather busy period for Athens and availability of hotels in the area is limited.

It is with great pleasure and anticipation that I extend a personal invitation to you to attend the upcoming Perlite Institute Annual Meeting in Athens, Greece. It is scheduled for September 17 – 20, 2023.

Our company has been a long-time member of the Perlite Institute. Over the years, I have seen the value that comes from our members getting together to network and share their expertise and leadership. I believe our members’ participation in this annual meeting greatly enriches discussions and contributes to the exchange of knowledge and ideas that benefits us all!

Every year, we hear stories about the value of the Perlite Institute Annual Meeting. This year, we will feature a diverse array of speakers and networking opportunities, all aimed at exploring the latest advancements and trends within our industry. I am especially excited that we will have a private tour of some of Imerys' operations on the beautiful island of Milos.

The Perlite Institute has been intentional about connecting our global community for many, many years. It is important to collaborate and learn together, as well as make connections that lead to fruitful collaborations, partnerships, and long-time friendships. Don’t miss this opportunity to be part of this amazing experience!

Space is limited, so do not delay in making your hotel and meeting reservations.

I look forward to seeing you in Greece!

Best Regards,

Jake

PERLITE TODAY PERLITE TODAY

PERLITE INSTITUTE, INC. is a quarterly publication of the PERLITE INSTITUTE, INC.

2207 Forest Hills Drive Harrisburg, PA 17112 USA Phone: 717.238.9723

Fax: 717.238.9985

www.perlite.org

2023 Board of Directors

Jake Hess President Hess Perlite 100 Hess Drive Malad City, ID 83252 Phone: (208) 766 - 4777 jake@hesspumice.com

Alan Kiraly Vice President Supreme Perlite 4600 N. Suttle Road Portland, OR 97217 Phone: (503) 286 - 4333 alan@supremeperlite.com

Perlite Today is published electronically four times per year.

Reema Bolokbaeva Gulf Perlite, LLC Techno Park, PO 263275

Jebel Ali, Dubai, UAE Phone: +971 (0)56 6080223 admin@uaeperlite.com

Linda Chirico Carolina Perlite Company PO Box 158 Gold Hill, NC 28071 Phone: (704) 279-2325 lchirico@carolinaperlite.com

Michael Dunlavey P.V.P. Industries PO Box 129 North Bloomfield, OH 44450 Phone: (440) 685-4701 mike@pvpind.com

Israel Ferreres Treasurer Ausperl 177 Balmes Street Barcelona, Spain 08006 +34 633 066 006 israel@ausperl.com

Keith Hoople Past President Midwest Perlite, Inc. 4280 West Parkway Blvd. Appleton, WI 54913

Phone: (920) 731-2671 keith@midwestperlite.com

Jannick Knudsen

Nordisk Perlite

Hammersholt Erhvervspark 1-5 Hillerod, DK 3400

Phone: 0045 7878 9515 jannick@nordiskperlite.dk

Bridget Sheehy Tipton Whittemore Company 681 East 5th Street, Unit 1 Boston, MA 02127

Phone: (978) 815-6420 bsheehy@whittemoreco.com

Edgar Valmana Velazquez

Termolita

Callejon del Marmol 201 Zona Industrial Santa Catarina, NL 66364

The mission of the Perlite Institute is to further the success and growth of the perlite industry worldwide by providing its members networking opportunities, education and research; foster customer-driven marketing, promotion and product development; and increase the public’s awareness and knowledge of perlite and its current and potential uses.

Matt Goecker Dicalite Management Group 1 Belmont Avenue, Suite 500 Bala Cynwyd, PA 19004 Phone: (775) 287-9796 mgoecker@dicalite.com

Phone: +52 8181510480

evalmana@termolita.com

Technical Q&As

Inquiring Minds Want to Know More About Perlite!

by Chuck Vogelsang, Perlite Institute Technical Consultant

The number of inquires the first five months of the year were two-thirds the quantity of last year for this same time frame.

The majority of the inquiries continue to be in the construction, environmental, filtration, and insulation areas.

Construction:

• Inquirer wanted information on perlite plasters. Provided our PI bulletins on this.

• Company wanted possible sources of expanded perlite in the Carolinas. Provided information on Carolina Perlite and Nor Cal Perlite, Inc.

• Inquirer was interested in lightweight perlite plaster formulations. Provided information on formulations and various grades of expanded perlite.

• Homeowner wanted lightweight concrete formula for 600 psig. Sent our lightweight concrete and transit mix bulletins as well as where to get material. Emphasized not to use horticultural material as found in Home Depot type supply places.

Chuck Vogelsang, Perlite Institute Technical Consultant

• Possible mixes for prefab products that could be used in the reconstruction effort in Ukraine. Put them in touch with Lydia.

• Person wanted information on lightweight concrete for use in a LNG project. The mix would be dependent on the required structural strength required. They also wanted to use lightweight concrete for containment and trenches. Sent our PI bulletin on underground trenches.

• Inquirer wanted information on repairing roofdecks and flooring. Provided a number of our PI bulletins on roofdecking.

• Person wanted guidance on using loose fill for swim pool insulation. Recommended lightweight concrete rather than loose-fill. They also were interested in precast brick or tile for pool insulation

• User wanted information on rooftop mixes. Provided PI bulletins on these.

Filtration:

• PI member interested in edible oil filtration and what would be required to make it. Did a Zoom call covering what is involved and sent a copy of my recent PFA presentation.

• Utility group wanted to know what PFA grade would be good for water filtration. Recommended consulting with the filter manufacturer as to the desired throughput rate for the filter, the clarity required, and particulate loading. Sent our PI bulletins on perlite filteraid for vacuum and pressure filtration, perlite filteraids explained, and perlite for filtration.

Continued on next page...

Environmental:

• Homeowner learned that her popcorn ceiling contained perlite. There were white particles on the floor over time which was concerning. She was informed perlite was a silica and that silica was a possible carcinogen. She reacted by moving out of the house until possible solutions could be developed. Informed homeowner that expanded perlite did not contain crystalline silica which is where the concern is and not with amorphous silica. Any concern would be with respirable size material not coarse particles. Then provided our PI bulletins on characteristics of perlite, and health effects of perlite.

• Purina was soliciting ideas as to how to dispose of unwanted expanded perlite fines. Provided bulletins: perlite as an absorbent or carrier, perlite as a sludge absorbent, perlite for lawns and gardens, and water holding capacity of perlite.

• Group requested information on estimating CO2 for expanded perlite. Explained how each step in the process had to be estimated plus was quite dependent on transportation distances and mode. Emphasized there is quite a difference in CO2 required at the source of each step. If one was looking at total life cycle that this is where perlite had a great advantage versus other competitive materials.

• Landlord found old bags of Permalite insulation in the attic. Wanted to know what options were available for disposal. Provide PI bulletins on lawn and garden use, absorption properties, and that it was an inert material used in clean up of oils for disposal in landfills.

Horticulture:

• California BLM geologist was interested in how to determine if ore samples were perlite. The interest was if it was good for horticulture. Had extensive Zoom call on perlite ore deposits, processing and expansion. Discussed the horticulture market in U.S. Chemical analysis alone is not adequate. Then provided names of services to test ores.

• Received questions on grow bag design – why holes are in their specific locations. Sent our PI bulletin as well as information from Gulf Perlite.

Industrial:

• Major board plant employee wanted to know microsphere suppliers on East Coast. Provided contact information for Dicaperl and Silbrico.

How to Find and Develop Your Vision

by Jeff Tippett

Have you ever played a board game with friends and everyone starts to quibble over the rules midway through the game? It might have seemed as if you were on the same page, but if it comes to a point where your mutual understandings of the game fall apart, and it’s impossible to complete the game.

The same threat applies to your business. If you assume that everyone understands the rules of the game and your vision for progression, things will probably seem to be going fine. But then, inevitably, something will happen. Someone will be unsure of the goal or the path to get there. This is where a firmly and clearly articulated vision comes into play.

It’s imperative that you develop a clear understanding of your vision, but, of course, you may need help in building out that vision. It may not be initially apparent. That’s perfectly natural.

The first step in finding and developing your vision is to narrow it. It needs to be rather specific, and achievable. “Making the world a better place” is as noble as any vision statement, but is it something that you alone can achieve? Moreover, there’s not likely a clear path to achieving it. Be bold, but realistic. Your vision should be the most you can reasonably expect to achieve.

Another aspect to consider is whether you’ve crafted your vision in terms that are concrete. This is a concept similar to one that I cover in my last book, Unleashing Your Superpower. When conveying your vision, be sure to use specific language, not abstract. Fully describe the goals and how you expect to reach them.

For example, which makes more sense in terms of really understanding the goal? (1) “We will lead the market in production” or (2) “We will become the preeminent supplier of this product, overtaking competitors while maintaining outstanding quality.” The same message is being conveyed, but the second option adds meat to it and makes clear that the goal is more than just making money; it’s about maintaining the work ethic and quality that brought your business to this point.

Concrete language focused on a narrow message is critical to improving your vision statement and ensuring that everyone buys in. And having a shared resolve among your team is indispensable. There’s a difference between a vision and a shared vision. A successful leader nurtures the latter. You can’t lead if the rest of your team is blindfolded. Ensure that they understand the goal and that there are clear benchmarks along the way so that everyone can stay on track and recognize progress.

A good leader doesn’t just lead; a good leader listens. Solicit feedback from your team on a regular basis, but particularly when moving in a new direction. Some folks will be hesitant to speak up if they have questions or concerns. But when encouraged to do so, they’ll be more inclined to speak up. Just because someone doesn’t tell you they have an issue doesn’t mean they’re completely on board. Take time to address concerns.

I like this quote from Antoine de Saint-Exupery: “If you want to build a ship, don’t drum up men to gather wood, give orders and divide the work. Rather, teach them to yearn for the far and endless sea.”

Remember: Everything isn’t about you. If you can focus on the win for your team and how change can be a good thing for them, they’ll join you on the journey without issue.

You also want to remember that everyone in the digital age has 50 things competing to take their attention in 50 different directions. Make your message short and sweet. Take, for example, IKEA’s: “Our vision is to create a better everyday life for many people.” That’s it. But it captures everything about their organization, and every member of their organization can understand and recite it. It’s also obvious to every person involved how their individual role impacts the mission, be it as a customer-facing clerk or as the chief financial officer. The goal remains the same.

Take these suggestions and begin thinking about how your vision statement might look and how to make it narrow, concrete and easy for your team to absorb. This isn’t everything you’ll need to perfect your vision statement, but it should be a groundwork upon which you can build.

About the Author: Jeff Tippett

Jeff Tippett is the international best-selling author of two books, Pixels Are the New Ink and Unleashing Your Superpower: Why Persuasive Communication is the Only Force You Will Ever Need. Speaking to international audiences through keynotes and seminars, Jeff helps attendees

increase their effectiveness, gives them powerful tools to reach their goals, and empowers attendees to positively impact and grow their organizations or businesses.

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In 2014, Jeff founded Targeted Persuasion, an award-winning public affairs + communications firm. He has worked with renowned brands like Airbnb, The National Restaurant Association, The League of Women Voters, The League of Conservation Voters, plus others. Other industry experts have validated Jeff’s work with numerous awards including the prestigious The American Advertising Award.

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Jeff is the host of Victory by Association with Jeff Tippett, a podcast that shares the victories of association executives with the world, highlighting the great work done across this country every day.

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Speaking of Perlite

by Panagiotis Angelopoulos, Perlite Institute Technical and Marketing Consultant

Removal of Heavy Metal Ions Using Perlite as Absorbent

Heavy metals are defined as those metals and metalloids generally considered to be of sufficient distribution and abundance as to be in some way environmentally or biologically significant as a toxic substance. The removal of heavy metals from waters and wastewaters is important in terms of protection of public health and environment due to their accumulation in living tissues throughout the food chain as a non-biodegradable pollutant. The effluents of a wide range of industrial applications, including microelectronics, electroplating, battery manufacture, dyestuffs, pharmaceutical, metallurgical, chemicals and many others causes heavy metals pollution in the environment. Commonly, Cadmium (Cd), copper (Cu), lead (Pd), chromium (Cr), nickel (Ni), and zinc (Zn) are among the heavy metals that contaminate effluents and are considered for removal before disposal by different techniques including ion-exchange, solvent extraction, chemical precipitation, phytoextraction, ultrafiltration, reverse osmosis, electrodialysis and adsorption.

Expanded perlite is an economical adsorbent, constituting an attractive choice in the removal of metal ions from wastewaters and water supplies. Therefore, its adsorption performance in aqueous environments with the presence of various heavy metals have been the objective of research studies, which is worth the attention of perlite industry since they provide useful application information, as well as proof of the concept. In this article, I am presenting some of the most characteristic ones per metal.

The adsorption of cadmium has been investigated by Mathialagan and Viraraghavan [1]. The authors used perlite powder studying the effect of time, initial metal concentration, adsorbent dosage and pH. It was found out that the optimum pH was 6. Also, the residual concentration of Cadmium reached equilibrium in 6 h, and the rate of Cadmium adsorption was rapid in the first hour of reaction time.

The adsorption of Cadmium onto perlite appears to follow a high correlation factor of pseudo-second-order kinetics (PSO). The experimental data indicated that the maximum adsorption capacity of Cd was 0.64 mg/g.

Cu (II) Pb (II):

Copper and lead adsorption

using perlite was investigated by Sari et al [2]. In this analysis, the batch system using perlite powder as an adsorbent was studied as a function of effects of time (5–120 min), initial metal concentration (0–400 mg/L), the dosage of adsorbent (2–40 g/L) and pH (2–9). In addition, to calculate the thermodynamic terms, at various temperatures of 293, 303, 313, and 323 K, experiments were conducted. It was found out that the maximum absorption of Cu(II) and Pb(II) ions occurs at a pH of about 5. At pH above 5, the metal deposition was formed, and the adsorbent became unusable with the accumulation of metal ions. At 293–323 K, the adsorption efficiency of Copper (II) and Lead (II) ions on expanded perlite rise with a rising contact time of up to 90 min. The maximum adsorption was 97% for Pb(II) ions and 80% for Cu(II) ions at 90 minutes at 20 ◦ C. The maximum adsorption capacity of Cu(II) and Pb(II) on perlite using the Langmuir model was 8.62 mg/g and 13.39 mg/g, respectively. Other important data provided by the authors are the mean free energy values obtained from the model (DR) for Cu(II) and Pb(II) on perlite which was 10.82 kJ/mol and 9.12 kJ/mol, respectively, showing that the process adsorption of these heavy metals on expanded perlite probably occurs through a chemical ion-exchange mechanism.

Cr

(III): The

health and environmental effects of carcinogenic Cr(VI) are well known. If Fe(II), HSO3, or another electron donor such as organic matter is present, Cr(VI) can be reduced to Cr(III), which tends to be attenuated in soil by inorganic phases such as phyllosilicates and hydroxides. Chakir et al investigated the use of perlite for Cr(III) adsorption [3]. The amount of Cr(III) adsorption on perlite increases with increasing pH and reaches the maximum value at pH equal to 5. The adsorption of Cr(III) on the expanded perlite is slow, and equilibrium was achieved after about 15 hours. The removal efficiency reached 40%.

Panagiotis Angelopoulos

Sr, Ba:

Torab-Mostaedi et al. reported the adsorption of strontium (Sr) and barium (Ba) using expanded perlite as an adsorbent [4]. Targeting to a cost-effective commercial product, the researchers used expanded perlite with no physical of chemical treatment. In this analysis, the batch system using expanded perlite powder as an adsorbent was studied as a function of the effects of time (5-360 min), initial metal concentration (5-50 mg/dm3 ), the dosage of adsorbent (1-18 g/dm3), and pH (2–7). Also, to calculate the thermodynamic terms, at various temperatures of 293, 303, 313, and 323 K, experiments were conducted. The pH range is limited to values equal to or less than seven because metal deposition occurs at higher pH. Like other cases, the percentage of adsorption increases with increasing pH and reaches the optimum value at pH 6. The adsorption of strontium and barium is fast, and the equilibrium time for both cations is 90 minutes. Adsorption efficiency increases with increasing adsorbent content. That is to be expected because the increase in the number of particles in the water provides these ions to interact with more adsorption sites. The experimental data showed that the maximum adsorption capacity of Sr(II) and Ba(II) ions was 1.14 mg/g and 2.486 mg/g, sequentially.

Ag (I), Cu (II) and Hg (II):

Ghassabzadeh et al. investigated the adsorption capacity of perlite to remove silver, mercury, and copper ions [5]. In this analysis, the batch system using perlite powder as an adsorbent was studied as a function of the effects of time (5-360 min), initial metal concentration (5-50 mg/L), the dosage of adsorbent (1-18 g/L) and pH (3-8). Also, to calculate the thermodynamic terms, at various temperatures of 293, 303, 313, and 323 K, experiments were conducted. Increasing the adsorbent causes a rapid increase in the adsorption of Silver(I), Cupper (II), and Mercury (II) to more than 99, 90, and 30%, sequentially. At pH less than 4, the percentage of adsorption of metal ions increases:

− MOH + H − OHH+→ MOH+2 + OH−

At higher pH values (between 4 and 6), the expanded perlite surface has a negative charge and therefore decreases with the increased pH of the solution.

− MOH ↔ − MO−+H+

A further increase in pH values leads to metal deposition and metal accumulation on the expanded perlite surface and the destruction of the adsorption mechanism. Therefore, a pH of 6.5 chooses as the optimal value in subsequent experiments. Increasing the contact time increases the adsorption percentage; the absorption of Ag(I), Cu(II), and Hg(II) reach maximum values in 120, 240, and 240 minutes, respectively. Further increase in contact time has no significant effect on adsorption. Thermodynamic results also show an exothermic process. The adsorption Ag(I), Cu(II), and Hg(II) onto expanded perlite appear to follow a high correlation factor of pseudosecond-order kinetics (PSO). The experimental data showed that the maximum adsorption capacity of Ag(I), Cu(II), and Hg(II) ions to be 8.46 mg/g, 1.95, and 0.35 mg/g, respectively, with a perfectly fitted to the Langmuir isotherm model.

Cd, Ld:

Malakootian et al. studied the adsorption capacity of perlite to remove lead (Ld) and cadmium (Cd) from paint-manufacturing effluent [6]. In this analysis, the batch system using perlite powder as an adsorbent was studied as a function of the effects of initial metal concentration (11 mg/LPb and 2.6 mg/LCd), contact time (10–120 min), the dosage of adsorbent (1–10 g/L), and pH (3–10). It was found out that the uptake rate raised with the incremental raising of the adsorbent quantity with (10 g/L) of expanded perlite and pH = 7, the rate reached a maximum level of 100% for Ld and 97.7% for Cd. Based on these outcomes, a contact time of 90 min for both ions was appropriate for the next sorption experiments. The adsorption of lead and cadmium is optimal in alkaline conditions.

Ni(II), Pb(II), and Cd(II):

Vijayaraghavan and Raja investigated the adsorption performance of perlite in up taking Cu(II), Ni(II), Pb(II), and Cd(II) making experiments in single and quaternary solutions [7]. The pH of the solution is the most critical parameter that controls the uptake of metal ions. Results illustrated that extent of sorption for perlite was in the order of Pb>Cu>Ni>Cd at optimum pH of 5 and initial solute concentration of 0.5±0.02 mmol/L within 480min.

Interestingly, expanded perlite is a functional sorbent (even partially) for the studied heavy metals. The studies show that expanded perlite can potentially been considered as an effective adsorbent, provided that its function has been optimised for the specific effluent type.

Density, porosity and specific surface area are important material parameters that affect the adsorption capacity, thus needs to be considered. Regarding the process conditions, the contact time, pH and adsorbent dosage are of high importance thus needs to be studied for the determination of optimum application conditions. Often, effluents are contaminated with more than one heavy metals. In that case, the combination of expanded perlite with another sorbent, i.e. bentonite may be applied providing with an integrated environmental solution.

Bibliography

1. Mathialagan T, Viraraghavan T. Adsorption of cadmium from aqueous solutions by vermiculite. Sep Sci Technol. 2003;38:57–76.

2. Sarı A, Tuzen M, Cıtak D, Soylak M. Adsorption characteristics of Cu ( II ) and Pb ( II ) onto expanded perlite from aqueous solution. 2007;148:387–94.

3. Chakir A, Bessiere J, Kacemi KEL, Marouf B. A comparative study of the removal of trivalent chromium from aqueous solutions by bentonite and expanded perlite. J Hazard Mater. 2002;95:29–46.

4. Torab-Mostaedi M, Ghaemi A, Ghassabzadeh H, Ghannadi-Maragheh M. Removal of strontium and barium from aqueous solutions by adsorption onto expanded perlite. Can J Chem Eng. 2011;89:1247–54.

5. Ghassabzadeh H, Mohadespour A, Torab-Mostaedi M, Zaheri P, Maragheh MG, Taheri H. Adsorption of Ag, Cu and Hg from aqueous solutions using expanded perlite. J Hazard Mater. Elsevier B.V.; 2010;177:950–5.

6. Malakootian M, Jaafarzadeh NA, Hossaini H. Efficiency of perlite as a low cost adsorbent applied to removal of pb and cd from paint industry effluent. Desalin Water Treat. 2011;26:243–9.

7. Vijayaraghavan K, Raja FD. Journal of Water Process Engineering Experimental characterisation and evaluation of perlite as a sorbent for heavy metal ions in single and quaternary solutions. J Water Process Eng. Elsevier Ltd; 2014;4:179–84.

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