Difference between revisions of "Silica gel, commercial"

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**This record is in progress. Please do not link or cite
 
**This record is in progress. Please do not link or cite
 
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==Description==     
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==Description==
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{| class="wikitable"
 +
|-
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! Brand  name
 +
! Company
 +
! Composition
 +
! Pre-conditioned RH options
 +
! Humidity for usage
 +
! Comments/Forms
 +
! Web page for more info
 +
|-
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| Arten  Gel
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| Art Preservation Services
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| type A SiO2
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| 0% 30% 40%
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| Best for 0-40% range; avg value  of MH* is 5 in range
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| 8 mesh beads (2mm diameter) in  moisture permeable bag
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| APSNYC: [https://www.apsnyc.com/products Product page]
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|-
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| Art Sorb
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| Fuji Silysia
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| 90% SiO2 10% LiCl
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| 0% 40% 45% 50% 55% 60%  65% 70%
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| Best from 40-70%
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| Prosorb site says Art Sorb is  best from 60-80%; beads, sheets, cassettes
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| Fuji Silysia: [https://www.fuji-silysia.co.jp/en/products/p906/ Art Sorb]
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|-
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| Moisture  Pak
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| Sorbent Systems
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| cellulose, water, salts
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| 62% +/- 3% in sealed container
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| same
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| food storage, tobacco, wood  instruments, herbs; variable size packets
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|
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|-
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| Prosorb
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| Sercalia
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| 97% SiO2 3% Al2O3
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| 30%  35%  40% 45%   50%  55%  60%
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| Optimum between 30-60% range
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| similar performance as Rhapid  gel; beads, sachets, cassettes
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| Sercalia: [https://www.sercalia.com/en/prosorb-moisture-stabilizer/ Prosorb]
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|-
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| Rhapid  gel
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| Art Preservation Services
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| Hybrid SiO2
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| 0% 40% 45% 50% 60%
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| Best for 0-65% range; avg value  of MH* is 5 in range
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| flexible moisture-pearmeable  sachets
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| APSNYC: [https://www.apsnyc.com/products Products page]
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|-
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| Silica  gel E
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|
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| type A SiO2
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|
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| Best for 0-30%
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|
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|
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|-
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| Silica  gel orange
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|
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| type A SiO2 with methyl violet  indicator
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|
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| Best for 0-30%
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| moisture indicator: changes  orange to green as increases from 5 to 15%
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| AGM:  [https://www.agmcontainer.com/blog/desiccant/indicating-silica-gel/#:~:text=These%20indicators%2C%20typically%20either%20cobalt%20chloride%20or%20methyl,silica%20gel%20needs%20to%20be%20replaced%20or%20recharged.  Blue vs orange]
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|-
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| Silica  gel M
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|
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| macroporous
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|
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| Best for 80-100%
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| prevents condensation at high RH
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|
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|-
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| Grade 42
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|
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| type A SiO2 with cobalt  dichloride indicator
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|
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|
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| moisture indicator: changes blue  to pink as increases from 15-45%
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|
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|-
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| Grade 40
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|
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| type A SiO2
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|
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|
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| may be mixed with 42
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|
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|}
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==Moisture Reservoir Information== 
 
The moisture adsorbing properties of silica gels are affected by factors such as capillary pore size or the inclusion of hygroscopic salts, resulting in a wide range of performance. Thus, it is important to compare the buffering capacity of different types of silica gels to determine which has the best performance for a specific application. In 1977, Thomson described the specific moisture reservoir with the variable M where M represents the amount of water (in grams) that is gained or lost by 1 kilogram of silica gel for each 1% change in RH.  However for any specific silica gel type, M can vary widely due to the expected RH range and the hysteresis of the adsorption/desorption curve.  In order to compensate, a new value called M<sub>H</sub> has been defined as the average amount of water (in grams) that is gained or lost by 1 kilogram of silica gel for each 1% change in RH. This is determined by repeatedly cycling silica gel between adsorption and desorption within a specific RH range until a constant value is measured.  
 
The moisture adsorbing properties of silica gels are affected by factors such as capillary pore size or the inclusion of hygroscopic salts, resulting in a wide range of performance. Thus, it is important to compare the buffering capacity of different types of silica gels to determine which has the best performance for a specific application. In 1977, Thomson described the specific moisture reservoir with the variable M where M represents the amount of water (in grams) that is gained or lost by 1 kilogram of silica gel for each 1% change in RH.  However for any specific silica gel type, M can vary widely due to the expected RH range and the hysteresis of the adsorption/desorption curve.  In order to compensate, a new value called M<sub>H</sub> has been defined as the average amount of water (in grams) that is gained or lost by 1 kilogram of silica gel for each 1% change in RH. This is determined by repeatedly cycling silica gel between adsorption and desorption within a specific RH range until a constant value is measured.  
  
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Table 1: Specific moisture reservoir (g/kg for a 1% RH change) at 20°C *
+
Specific moisture reservoir (g/kg for a 1% RH change) at 20°C *
 
{| class="wikitable"  
 
{| class="wikitable"  
 
|-
 
|-
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! M 20 → 30%
 
! M 20 → 30%
 
! M 60 → 50%
 
! M 60 → 50%
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! Recommended for
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! Recommended amounts
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! Recommended for
 
 
|-
 
|-
 
| RH  around 50%
 
| RH  around 50%
 
| Keep RH low
 
| Keep RH low
 
| Keep RH high
 
| Keep RH high
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| Temp exhibit case in room with  good to moderate climate control
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| Depends on air flow and exhibit length
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| Maintenance-free exhibit case
 
 
|-
 
|-
 
| RHapid Gel
 
| RHapid Gel
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| 4.48 ±  0.42
 
| 4.48 ±  0.42
 
| 4.38 ±  1.40
 
| 4.38 ±  1.40
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| 2 kg/m3
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| 2-4 kg/m3
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| 4 kg/m3
 
 
|-
 
|-
 
| PROSorb
 
| PROSorb
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| 4.37 ±  0.10
 
| 4.37 ±  0.10
 
| 4.25 ±  0.38
 
| 4.25 ±  0.38
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|  
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| 2-4 kg/m3
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|
 
 
|-
 
|-
 
| Art-Sorb
 
| Art-Sorb
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| 2.84 ±  0.47
 
| 2.84 ±  0.47
 
| 4.18 ±  0.49
 
| 4.18 ±  0.49
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| 4 kg/m3
+
| 4-8 kg/m3
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| 8 kg/m3
 
 
|-
 
|-
 
| Arten  Gel
 
| Arten  Gel
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| 5.5
 
| 5.5
 
|  
 
|  
−
|  
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| 9-18 kg/m3
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|
 
 
|-
 
|-
 
| Regular density silica gel (clear, type A)
 
| Regular density silica gel (clear, type A)
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| 5.48 ±  0.40
 
| 5.48 ±  0.40
 
| 1.47 ±  0.16
 
| 1.47 ±  0.16
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| 9 kg/m3
+
| 9-18 kg/m3
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| 18 kg/m3
 
 
|-
 
|-
 
| Orange silica gel
 
| Orange silica gel
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| 4.92 ±  0.59
 
| 4.92 ±  0.59
 
| 0.94 ±  0.14
 
| 0.94 ±  0.14
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|  
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| 9-18 kg/m3
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|
 
 
|-
 
|-
 
| Bentonite clay (Desi Pak)
 
| Bentonite clay (Desi Pak)
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| 2.25 ±  0.03
 
| 2.25 ±  0.03
 
| 1.11 ±  0.02
 
| 1.11 ±  0.02
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|  
 
|  
 
|-
 
|-
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| 0.47 ±  0.04
 
| 0.47 ±  0.04
 
| 0.31 ±  0.01
 
| 0.31 ±  0.01
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|
 
 
|  
 
|  
 
|}
 
|}

Revision as of 10:14, 10 August 2023

    • This record is in progress. Please do not link or cite

.

Description

Brand name Company Composition Pre-conditioned RH options Humidity for usage Comments/Forms Web page for more info
Arten Gel Art Preservation Services type A SiO2 0% 30% 40% Best for 0-40% range; avg value of MH* is 5 in range 8 mesh beads (2mm diameter) in moisture permeable bag APSNYC: Product page
Art Sorb Fuji Silysia 90% SiO2 10% LiCl 0% 40% 45% 50% 55% 60% 65% 70% Best from 40-70% Prosorb site says Art Sorb is best from 60-80%; beads, sheets, cassettes Fuji Silysia: Art Sorb
Moisture Pak Sorbent Systems cellulose, water, salts 62% +/- 3% in sealed container same food storage, tobacco, wood instruments, herbs; variable size packets
Prosorb Sercalia 97% SiO2 3% Al2O3 30% 35% 40% 45% 50% 55% 60% Optimum between 30-60% range similar performance as Rhapid gel; beads, sachets, cassettes Sercalia: Prosorb
Rhapid gel Art Preservation Services Hybrid SiO2 0% 40% 45% 50% 60% Best for 0-65% range; avg value of MH* is 5 in range flexible moisture-pearmeable sachets APSNYC: Products page
Silica gel E type A SiO2 Best for 0-30%
Silica gel orange type A SiO2 with methyl violet indicator Best for 0-30% moisture indicator: changes orange to green as increases from 5 to 15% AGM: Blue vs orange
Silica gel M macroporous Best for 80-100% prevents condensation at high RH
Grade 42 type A SiO2 with cobalt dichloride indicator moisture indicator: changes blue to pink as increases from 15-45%
Grade 40 type A SiO2 may be mixed with 42

Moisture Reservoir Information

The moisture adsorbing properties of silica gels are affected by factors such as capillary pore size or the inclusion of hygroscopic salts, resulting in a wide range of performance. Thus, it is important to compare the buffering capacity of different types of silica gels to determine which has the best performance for a specific application. In 1977, Thomson described the specific moisture reservoir with the variable M where M represents the amount of water (in grams) that is gained or lost by 1 kilogram of silica gel for each 1% change in RH. However for any specific silica gel type, M can vary widely due to the expected RH range and the hysteresis of the adsorption/desorption curve. In order to compensate, a new value called MH has been defined as the average amount of water (in grams) that is gained or lost by 1 kilogram of silica gel for each 1% change in RH. This is determined by repeatedly cycling silica gel between adsorption and desorption within a specific RH range until a constant value is measured.

Specific moisture reservoir (g/kg for a 1% RH change) at 20°C *

Moisture sorbent MH 50 ± 10% M 20 → 30% M 60 → 50% Recommended amounts
RH around 50% Keep RH low Keep RH high Depends on air flow and exhibit length
RHapid Gel 6.11 ± 2.16 4.48 ± 0.42 4.38 ± 1.40 2-4 kg/m3
PROSorb 5.42 ± 1.32 4.37 ± 0.10 4.25 ± 0.38 2-4 kg/m3
Art-Sorb 4.04 ± 0.80 2.84 ± 0.47 4.18 ± 0.49 4-8 kg/m3
Arten Gel 5.7 5.5 9-18 kg/m3
Regular density silica gel (clear, type A) 1.93 ± 0.44 5.48 ± 0.40 1.47 ± 0.16 9-18 kg/m3
Orange silica gel 1.16 ± 0.26 4.92 ± 0.59 0.94 ± 0.14 9-18 kg/m3
Bentonite clay (Desi Pak) 1.19 ± 0.07 2.25 ± 0.03 1.11 ± 0.02
Molecular sieves 4A (zeolite) 0.33 ± 0.02 0.47 ± 0.04 0.31 ± 0.01

Resources and Citations

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